YOU ARE HERE:

I want information on:

Information for:

#### NAM2011 Presentation Details

This is a complete listing of all 382 entries

First | Previous | Next | Last | All

The ZEPLIN-III Direct Dark Matter Search

Author: Alexander Murphy

University of Edinburgh

Co-Authors: Alex Murphy, for the ZEPLIN-III Collaboration

Session: APP: Astroparticle Physics

Presentation type: Talk

Summary:

The existence of dark matter, contributing significantly to the overall energy density of the Universe, has become one of pillars of modern cosmology. Similarly in particle physics, it is now viewed as perhaps the best evidence for new physics beyond the Standard Model. This is truly remarkable given that conclusive evidence of its existence has yet to be found. ZEPLIN-III, located at the Boulby mine in the north east of England, delivered one of the world's leading direct search results in its first science run. Following extensive upgrades, a second phase of data collection is underway. The present status will be presented.

Latest results from the Edelweiss dark matter search and future plans for EURECA

Author: Sam Henry

University of Oxford

Co-Authors:

Session: APP: Astroparticle Physics

Presentation type: Talk

Summary:

The Edelweiss dark matter search has set improved limits on dark matter using an array of ten 400g cryogenic germanium detectors, with interleaved electrodes to allow the identification of surface events and rejection of background events. This limit corresponds to a WIMP-nucleon scattering cross section of below 5x10^-8pb. Edelweiss now aims to improve this to 5x10^-9pb using a larger detector mass; and will be followed by the EURECA - a tonne scale dark matter experiment aiming to reach below 10^-10pb.

Background reduction & spin-dependent results from DRIFT

Author: Mark Pipe

University of Sheffield

Co-Authors:

Session: APP: Astroparticle Physics

Presentation type: Talk

Summary:

The DRIFT (Directional Recoil Identification From Tracks) collaboration operates a 1 m^3 scale, negative ion TPC dark matter detection experiment at the Boulby Mine, England. Recent detector upgrades allow the DRIFT-II detector to operate with CF4 gas added to the usual electronegative CS2 in order to give sensitivity to spin-dependent WIMP interactions. Results from underground runs with 30 Torr CS2 - 10 Torr CF4 partial pressures will be presented. Results will also be presented from recent efforts to reduce well understood backgrounds from radon progeny. Progress towards the scaled up DRIFT-III detector will also be presented.

The search for dark matter & beyond: Studies at the Boulby Deep Underground Science Facility

Author: Dr Sean Paling

STFC Boulby Underground Science Facility

Co-Authors:

Session: APP: Astroparticle Physics

Presentation type: Talk

Summary:

An overview of the astro-particle physics studies, ongoing and planned, at the UK's deep-underground low-background science facility at Boulby Mine. The talk will give details of the facilities available at Boulby, an overview of studies underway (in particular the ZEPLIN and DRIFT dark matter search experiments and the SKY cosmo-climatology study), as well as plans for future studies in astroparticle physics and beyond.

Classical dSphs as prospective targets for the indirect detection of dark matter with gamma rays

Author: Michael Daniel

University of Durham

Co-Authors: A. Charbonnier (CNRS-IN2P3); C. Combet (University of Leicester); S. Funk (SLAC); J. Hinton (University of Leicester); D Maurin (CNRS-IN2P3); C. Power (University of Leicester); J. Read (University of Leicester); S. Sarkar* (University of Oxford); M.W. Walker (University of Cambridge); M.I. Wilkinson (University of Leicester) * present

Session: APP: Astroparticle Physics

Presentation type: Talk

Summary:

Dwarf spheroidal galaxies (dSphs) consitute prime targets for the indirect detection of dark matter (DM) through gamma-ray observations. In this presentation we revisit the issue of their detectability for present and future gamma-ray observatories. The main innovative features of our analysis are: i) we perform a generic calculation of the â€˜astrophysical factorâ€™ J of the dSph gamma-ray flux and possible boost by the DM subclumps within the dSph; ii) we isolate the key parameters which enable comparison of the sensitivity of future gamma-ray observatories to these objects; iii) we derive the DM profiles and the expected gamma-ray fluxes of the classical dSphs using a Markov Chain Monte Carlo (MCMC) technique applied to photometric and kinematic data and quantify their detectability at 68% and 95% confidence level (CL); iv) We discuss the biases of the analysis and validate the latter on simulated DM profiles.

Asymmetric dark matter and the Sun

University of Oxford

Co-Authors: S. Sarkar (University of Oxford)

Session: APP: Astroparticle Physics

Presentation type: Talk

Summary:

Cold dark matter particles with an intrinsic matter-antimatter asymmetry do not annihilate after gravitational capture by the Sun and can affect its interior structure. The rate of capture is exponentially enhanced when such particles have self-interactions of the right order to explain structure formation on galactic scales. A â€œdark baryonâ€ of mass 5 GeV is a natural candidate and has the required relic abundance if its asymmetry is similar to that of ordinary baryons. Such particles have an effect on low energy Solar neutrino fluxes which may be measurable by the Borexino and SNO+ experiments.

Gravitational Wave Astronomy

Author: Giles Hammond

SUPA, University of Glasgow

Co-Authors:

Session: APP: Astroparticle Physics

Presentation type: Talk

Summary:

Einsteinâ€™s general theory of relativity predicts that rapidly accelerating massive objects lose energy in the form of gravitational waves. Although no direct detection has been made there is strong indirect evidence for this emission through the change in the orbital characteristics of the Hulse-Taylor binary system PSR 1913+16. There currently exist several classes of astrophysical object that are expected to be strong emitters of gravitational waves including gamma-ray bursts, soft-gamma repeaters, supernovae, glitching pulsars and coalescing compact binary systems. Over the past two decades, a world-wide effort to detect gravitational waves has led to the development of a network of ground-based interferometric detectors such as GEO, LIGO and VIRGO. These detectors are currently undergoing upgrades to 2nd generation status which will see their sensitivity increase by an order of magnitude. Combined with complimentary electro-magnetic detectors this will signal the beginning of the multi-messenger view of the Universe, and open up the gravitational window on the Universe. This talk will provide an overview of the main astrophysical sources, provide a status on detectors and planned hardware upgrades, and look to the future of ground based and space-based gravitational wave detection.

Particle acceleration at supernova remnant shocks

Author: Brian Reville

University of Oxford

Co-Authors: A.R. Bell, K.M. Schure

Session: APP: Astroparticle Physics

Presentation type: Talk

Summary:

It is believed that the majority of galactic cosmic rays are accelerated in supernova remnants. The most promising mechanism for generating and maintaining the non-thermal cosmic-ray spectrum is the first-order Fermi process, otherwise known as diffusive shock acceleration. Despite considerable progress in terms of multi-wavelength observations of nearby supernova remnants, conclusive evidence of cosmic-ray acceleration remains elusive. One of the major advances in recent years has been the detection of strongly amplified magnetic fields in the vicinity of the shock. Such amplification, well in excess of simple shock compressed ISM values, is necessary to confine particles close to the shock, and may facilitate the acceleration to the energies required to explain the cosmic ray 'knee' at ~3 PeV. A brief review of how these processes may occur is presented and some recent developments are discussed.

Probing quantum-gravity effects through blazar variability studies at very high energies

Author: Dimitrios Emmanoulopoulos

University of Southampton

Co-Authors:

Session: APP: Astroparticle Physics

Presentation type: Talk

Summary:

Einstein postulated that â€œLight always propagates through a vacuum at a definite velocity, c, which is independent of the state of motion of the emitting bodyâ€. This is the framework of classical special relativity, which has no fundamental length-scale associated with it and exhibits such a Lorentz invariance. However, quantum effects at the Planck scale where gravity becomes a strong force, are generally expected (although this is not yet proven) to strongly affect the nature of space-time, causing violations of Lorentz boost invariance. Such violations can be tested by measuring time-lags between very high energy photons emitted simultaneously from distant astrophysical sources, expressing possible variations of photon speed as a function of energy. Blazars are ideal sources for such studies due to their distance and their variability properties at very high energies (VHE), up to few TeV. Under the assumption that the source does not conspire to produce VHE photons with intrinsic time-delays which always cancel such effects, cross-correlation and maximum-likelihood analysis techniques can be used in order to set constraints on any energy dependence of the speed of light.

Recent Results from VERITAS

Author: John Quinn

University College Dublin

Co-Authors:

Session: APP: Astroparticle Physics

Presentation type: Talk

Summary:

VERITAS is an array of four imaging atmospheric Cherenkov telescopes, located in southern Arizona, for gamma-ray astronomy above 100 GeV. VERITAS has been fully operational since September 2007 but was reconfigured in 2009 through the relocation of a telescope to provide enhanced sensitivity. The VERITAS collaboration conducts a comprehensive scientific program that includes studies of galactic and extragalactic particle accelerators, gamma-ray burst follow-up observations, and the search for evidence of supersymmetric dark-matter self-annihilation. To date, VERITAS has detected in excess of 30 sources of TeV gamma rays including active galactic nuclei, shell-type supernova remnants, pulsar wind nebulae, a binary system, a starburst galaxy, and several unidentified sources. This talk will provide a status update on VERITAS and its science results, with emphasis on recent discoveries.

Status of H.E.S.S.

Author: Michael Daniel

University of Durham

Co-Authors: for the H.E.S.S. Collaboration (see http://www.mpi-hd.mpg.de/hfm/HESS/pages/collaboration for a listing of members)

Session: APP: Astroparticle Physics

Presentation type: Talk

Summary:

The High Energy Stereoscopic System is an array of imaging atmospheric Cherenkov telescopes sited in the southern hemisphere. It is currently the world's most sensitive instrument for the detection and observation of very high energy (VHE, E>100 GeV) gamma ray sources, with its location providing an excellent vantage to survey the galactic plane in addition to targeted observations of both galactic and extra-galactic objects. This talk will summarise the status of the instrument and review the latest results from the observational programme.

Very high energy gamma ray astronomy with CTA

Author: Johannes Knapp

U of Leeds

Co-Authors: The CTA Collaboration

Session: APP: Astroparticle Physics

Presentation type: Talk

Summary:

The Cherenkov Telescope Array (CTA) is a next-generation gamma ray observatory with greatly improved sensitivity and angular resolution in the energy range 50 GeV to >100 TeV. CTA will provide guaranteed high-energy astrophysics results and have a large discovery potential in key areas of astronomy, astrophysics and fundamental physics research. These include the study of the origin of cosmic rays and their impact on the constituents of the Universe through the investigation of galactic particle accelerators, the exploration of the nature and variety of black hole particle accelerators through the study of the production and propagation of extragalactic gamma rays, and the examination of the ultimate nature of matter and of physics beyond the Standard Model through searches for dark matter and the effects of quantum gravity. CTA will consist of up to 100 imaging air Cherenkov telescopes from 4 to 23 m diameter, at two sites (S and N). With 25 countries involved, CTA is a truly world-wide effort. The science potential and the status of the project will be presented.

Ultra high energy cosmic rays and recent results from the Pierre Auger Observatory.

Author: Johannes Knapp

University of Leeds

Co-Authors:

Session: APP: Astroparticle Physics

Presentation type: Talk

Summary:

Since almost 50 years the origin of ultra high energy cosmic rays (E > 10^18 eV) is a mystery. In recent years the Pierre Auger Collaboration has made a bold attempt to advance our knowledge on these cosmic particles with energies a million times more energetic than what LHC can deliver. Data of unprecedented quality and statistics have been recorded and intriguing answers have been found, yet (some of) the mystery persists. The recent results of the Pierre Auger Observatory will be presented.

Latest results from IceCube

Author: Robert Franke

DESY Zeuthen

Co-Authors: for the IceCube collaboration

Session: APP: Astroparticle Physics

Presentation type: Talk

Summary:

The recently completed IceCube observatory, located at the South Pole, is the world's first 1 km^3 neutrino detector. Its primary goal is the observation of astrophysical neutrinos in the TeV to PeV energy range. I will present recent results on searches for diffuse all-flavour neutrino fluxes and point sources of muon neutrinos. Emphasis will be placed on searches for time dependent sources, either triggered by the observation (with photons) of flaring source candidates, or in an untriggered way, looking for time dependence in the neutrino data itself. Untriggered searches are also run on-line to trigger follow-up observations with other instruments. Two of these programs - one aiming at the detection of supernovae and GRBs, the other concentrating on AGNs - will be explained. Other IceCube physics e.g. the study of atmospheric neutrinos, neutrino oscillations and searches for new physics beyond the Standard Model will be highlighted.

The KM3NeT high-energy neutrino project

Author: Joachim Rose

University of Leeds

Co-Authors:

Session: APP: Astroparticle Physics

Presentation type: Talk

Summary:

KM3NeT is a pan-European collaboration of astroparticle physicsists currently designing a multiple cubic kilometre scale neutrino telescope for deployment in the Mediterranean Sea. The presentation will outline the broad physics and astrophysics programme that such a device can address. The current status of KM3NeT will be described including news on recent key design decisions as well as a summary site options and possible detector configurations. The sensitivity of such a detector to diffuse and point like sources will also be discussed.

Resonances in 19Ne with relevance to the astrophysically important 18F(p,Î±)15O reaction.

Author: David Mountford

University of Edinburgh

Co-Authors:

Session: APP: Astroparticle Physics

Presentation type: Poster

Summary:

The decay of 18F via Î²+ decay is the main source of gamma ray emission from novae. The main nuclear uncertainty in this process comes from the 18F(p,Î±) reaction, which proceeds through resonances in the compound nucleus, 19Ne. In 2006 Dufour and Descouvement[1] proposed, through microscopic techniques, the existence of two previously unseen energy levels in the 19Ne nucleus, at ~6 and 7.9 MeV. In light of this there have been two published attempts in the search for the higher of these states. While Dalouzy et al.[2] claim to have discovered the elusive state, Murphy et al.[3] find no such candidate. The aim of this work is to address this contradiction and come to a firm conclusion as to the possible existence of this new state. An experiment has taken place that uses a 4MeV/u 18F beam, degraded to ~1.9MeV/u, incident upon a thick CH2 target. The data is currently being analysed within the R-matrix formulism and preliminary results are presented here. [1] M. Dufour and P. Descouvement, Nucl. Phys. A785, 381 (2007) [2] J.C. Dalouzy et. al., Phys. Rev. Lett., 102, 162503 (2009) [3] A.S. Murphy et. al., Phys. Rev. C79, 058801 (2009)

Transition from star-forming to passive galaxies: is there a preferred halo mass?

Author: Will Hartley

University of Nottingham

Co-Authors:

Session: COS: Cosmology and large scale structure

Presentation type: Talk

Summary:

It is now well established that the most massive galaxies in the Universe were the first to complete their star-formation. Though they are found in the most massive dark matter halos in the present day, their halos would have been of much lower mass when this transition occured; similar perhaps to the host halo masses of galaxies undergoing this transition at z=0. In fact, plausible theoretical arguments have been put forward, stating that the mass of a galaxy's host halo stongly influences whether a galaxy can become passive or will continue to form stars. Using the large-scale distribution of a sample of galaxies we can infer the typical masses of the dark matter halos that host them. By constructing star-forming galaxies and passive samples over a wide range of redshifts and luminosities, we can therefore determine whether there is a characteristic halo mass at which galaxies end their active lives.

The Morphologies of Galaxies in the SDSS Baryon Oscillation Spectroscopic Survey from HST Imaging

Author: Karen Masters

ICG, University of Portsmouth

Co-Authors: C. Maraston, A. Beifiori, R. Nichol, D. Thomas, J. Pforr (ICG, Portsmouth); A. Leauthaud (LBNL); R. Mandelbaum (Princeton); K. Bundy (UC Berkeley).

Session: COS: Cosmology and large scale structure

Presentation type: Talk

Summary:

The SDSS-III Baryon Oscillation Spectrocopic Survey (BOSS) will measure redshifts for 1.4 million massive galaxies between 0.2

No size or mass evolution of the most massive galaxies since z~1

Author: Claire Burke

Liverpool John Moores University

Co-Authors: C. Collins (LJMU); J.P. Stott (Durham)

Session: COS: Cosmology and large scale structure

Presentation type: Talk

Summary:

Brightest cluster galaxies are the most massive, most luminous and most homogeneous galaxies observed in the Universe. We have determined scale sizes and stellar masses of these objects from samples at redshift ~1. We compare our mass estimates to low redshift results and our scale size results to a z~0.2 sample in a well matched waveband. We find that these galaxies have not increased in stellar mass or size since z~1, which is an unexpected result when compared to cosmological models. The lack of scale size increase is also in stark contrast to the recent findings for compact elliptical galaxies at high redshift, which have been found to increase in scale size by up to factors of 5 since z~1.

Accurate Cosmography with Time Delay Gravitational Lenses

Author: Phil Marshall

University of Oxford

Co-Authors:

Session: COS: Cosmology and large scale structure

Presentation type: Talk

Summary:

The time delays between the multiple images of gravitationally lensed quasars have long been known to enable a measurement of the Hubble constant, but we have only recently shown how, with careful modeling of enough high quality data, we can achieve comparable accuracy to other, better known cosmographic probes. After introducing and describing this experiment, I will discuss how we plan to build on it in the next decade, using PS1 and the Large Synoptic Survey Telescope to find, measure and select hundreds of suitable systems.

Callibrating the Baryon Acoustic Oscillations to the CMB: the Alcock-Paczynski test.

University College London

Co-Authors: Ofer Lahav (UCL); F.B.Abdalla (UCL); G. Hutsi (Tartu Observatory, Estonia, Max-Planck-Institut fÂ¨ur Astrophysik, Germany); A. Nusser (Technion, Israel)

Session: COS: Cosmology and large scale structure

Presentation type: Talk

Summary:

We examine the possibility of constraining cosmological parameters, by an application of the Alcock-Paczynski test on galaxy redshift surveys. We use the Baryon Acoustic Scale as a feature of known physical size and investigate how callibration of this scale to equivalent features in the CMB removes degeneracies between redshift space and geometric distortions, improving constraints on cosmological parameters. We carry out a Fisher matrix analysis on a toy model of the power spectrum to demonstrate the concept. We also do a more robust Monte Carlo exploration of parameter space and compare constraints. Applying the same methodology to a numerically produced power spectrum, we show that for small galaxy redshift surveys likelihoods in parameter spaces are often highly non-gaussian and thus constraints are poorly described by Fisher matrices. Future high volume sky surveys (like DESpec) have much more gaussian likelihoods in parameter spaces.

Cosmological Implications of Massive Clusters in the Early Universe.

Author: Ben Hoyle

ICC University of Barcelona

Co-Authors: R.Jimenez (ICC-UB);L.Verde(ICC-UB);S.Hotchkiss(University of Helsinki)

Session: COS: Cosmology and large scale structure

Presentation type: Talk

Summary:

The existence of very massive galaxy clusters in the high redshift Universe appear to be in some tension with WMAP5 LCDM. After describing the cluster dataset and work to quantify the level of tension with LCDM, I describe some modifications to our assumptions about the concordance cosmological model which allow for these massive clusters to exist.

EBEX: Current status and future plans.

Author: William Grainger

Cardiff University

Co-Authors: A. M. Aboobaker (University of Minnesota) P. A. R. Ade (Cardiff University); F. Aubin (McGill University); C. Baccigalupi (Scuola Internazionale Superiore di Studi Avanzati); C. Bao (University of Minnesota); J. Borrill (Lawrence Berkeley National Laboratory); C. Cantalupo (Lawrence Berkeley National Laboratory); D. Chapman (Columbia University); J. Didier (Columbia University); M. Dobbs (McGill University); J. Grain (Institut d-Astrophysique Spataile); S. Hanany (University of Minnesota); S. Hillbrand (Columbia University); J. Hubmayr (NIST); A. Jaffe (Imperial College); B. Johnson (University of California, Berkeley); T. Jones (University of Minnesota); T. Kisner (Lawrence Berkeley National Laboratory); J. Klein (University of Minnesota); A. Korotkov (Brown University); S. Leach (Scuola Internazionale Superiore di Studi Avanzati); A. Lee (University of California, Berkeley); L. Levinson (Weizmann Institute of Science); M. Limon (Columbia University); K. MacDermid (McGill University); T. Matsumura (California Institude of Technology); X. Meng (University of California, Berkeley); A. Miller (Columbia University); M. Milligan (University of Minnesota); E. Pascale (Cardiff University); D. Polsgrove (University of Minnesota); N. Ponthieu (Institut d-Astrophysique Spataile); K. Raach (University of Minnesota); B. Reichborn-Kjennerud (Columbia University); I. Sagiv (University of Minnesota); G. Smecher (McGill University); F. Stivoli (Institut National de Recherche en Informatique et Automatique); R. Stompor (CNRS, Laboratoire Astroparticule et Cosmologie); H. Tran (University of California, Berkeley); M. Tristram (Laboratoire de l'Accelerateur Lineaire); G. S. Tucker (Brown University); Y. Vinokurov (Brown University); A. Yadav (Institute for Advanced Study); M. Zaldarriaga (Institute for Advanced Study); K. Zilic (University of Minnesota);

Session: COS: Cosmology and large scale structure

Presentation type: Talk

Summary:

EBEX (E and B EXperiment) is a balloon-borne cosmic microwave background (CMB) polarization experiment designed to search for the small B-mode polarization signal imprinted on the CMB by gravity waves during inflation. If the signal not detected EBEX has the sensitivity to set a 2 sigma upper limit on the inflationary tensor-to-scalar ratio of 0.04. The instrument employs a 1.5m Gregorian-type telescope and up to 1697 bolometric TES detectors, working at 150, 250 and 410 GHz, all with a resolution of 8 arcminutes. The overall sky coverage during the planned 11 day flight is 350 square degrees, achieving a noise on Q & U of 1.2 microK per 8 arcminute squared pixel. Polarimetry is achieved by a continuously rotating achromatic half-wave plate, suspended on a superconducting magnetic bearing, and polarizing grid. We report on the 14-hour North America test flight and current integration progress for the long duration flight from McMurdo station planned for December 2011.

Bayesian cosmological parameter estimation from SNe Ia data.

Author: Marisa Cristina March

Imperial College London

Co-Authors: R.Trotta (Imperial College London) G.D.Starkman (Case Western Reserve) P.Berkes (Brandeis) P.M.Vaudrevange (DESY)

Session: COS: Cosmology and large scale structure

Presentation type: Talk

Summary:

We present a new method based on a Bayesian hierarchical model to extract constraints on cosmological parameters from SNIa data obtained with the SALT II lightcurve fitter. We demonstrate with simulated data sets that our method delivers considerably tighter statistical constraints on the cosmological parameters and that it outperforms the usual chisquare approach 2/3 of the times. As a further benefit, a full posterior probability distribution for the dispersion of the intrinsic magnitude of SNe is obtained. We apply this method to recent SNIa data and find that it improves statistical constraints on cosmological parameters from SNIa data alone by about 40% w.r.t. the standard approach. Applications to systematic uncertainties will be discussed in a forthcoming paper.

Testing WMAP cosmology via the Planck Early Data Release

Author: Tom Shanks

Durham University

Co-Authors: J. Whitbourn (Durham University); U. Sawangwit (Durham University)

Session: COS: Cosmology and large scale structure

Presentation type: Talk

Summary:

The prime evidence underpinnng the standard LCDM model of cosmology is the CMB power spectrum as observed by WMAP and previous microwave experiments. But Sawangwit & Shanks (2010) showed that the WMAP CMB power spectrum was highly sensitive to the beam profile of the WMAP telescope and also that the beam profile measured by stacking WMAP radio (point) sources was broader than estimated by the WMAP team. In new work, Whitbourn et al (2011) have now used the Planck Early Data Release to test further the WMAP data. We find that there appears to be a scale error between the fluxes of radio sources measured in the same bands by WMAP and Planck, similar to our previous comparison between WMAP and ground-based data. Further, the stacked SZ decrements of ~150 galaxy clusters observed by Planck appear to be underestimated in the WMAP data by a factor of ~2 in the Q, V and W bands. Possible explanations for these apparent discrepancies will be briefly discussed.

On the evolution of non-Gaussianity to the adiabatic limit

Author: Joseph Elliston

Queen Mary, University of London

Co-Authors:

Session: COS: Cosmology and large scale structure

Presentation type: Talk

Summary:

An observation of non-Gaussian temperature fluctuations in the CMB would be a powerful tool in distinguishing between different theories of inflation. However, predictions for a given theory are only valid when an adiabatic limit has been reached, because only after reaching this limit are the curvature perturbation and its statistics conserved. This subtlety is particularly relevant in the well-studied case of multi-field inflation where a measurable non-Gaussianity can arise due to non-adiabatic perturbations. We therefore classify multiple field models of inflation depending upon the phase of evolution in which the adiabatic limit is reached; whether it is reached during slow-roll, after slow-roll ends but before reheating occurs, or only after reheating. This classification allows us to define whether analytic or numeric tools are appropriate to derive accurate results. We graphically illustrate results from each of the three classes using a collection of existing models as well as new ones, all of which are interesting in that they exhibit large non-Gaussianities at the adiabatic limit.

Second Order Perturbations During Inflation Beyond Slow-roll

Author: Ian Huston

Queen Mary, University of London

Co-Authors: K.A.Malik (Queen Mary, University of London)

Session: COS: Cosmology and large scale structure

Presentation type: Talk

Summary:

Cosmological perturbation theory is well established as a tool for probing the inhomogeneities of the early universe. In this talk I will motivate the use of perturbation theory and outline the mathematical formalism. Perturbations beyond linear order are especially interesting as non-Gaussian effects can be used to constrain inflationary models. I will show how the Klein-Gordon equation at second order, written in terms of scalar field variations only, can be numerically solved. This procedure allows the evolution of second order perturbations in general without the need for any slow roll approximation. I will also discuss extending the calculation to consider the non-Gaussianity of the field perturbations.

Higher-order Statistics for 3D Weak Lensing

Author: Dipak Munshi

Cardiff University

Co-Authors: Peter Coles (Cardiff University) Alan Heavens (Institute for Astronomy, Edinburgh)

Session: COS: Cosmology and large scale structure

Presentation type: Talk

Summary:

Weak gravitational lensing on a cosmological scales can provide strong constraints both on the nature of dark matter and the dark energy equation of state. Most current weak lensing studies are restricted to (two-dimensional) projections, but tomographic studies with photometric redshifts have started, and future surveys offer the possibility of probing the evolution of structure with redshift. In future we will be able to probe the growth of structure in 3D and put tighter constraints on cosmological models than can be achieved by the use of galaxy redshift surveys alone. Earlier studies in this direction focused mainly on evolution of the 3D power spectrum, but extension to higher-order statistics can lift degeneracies as well as providing information on primordial non-gaussianity. We present analytical results for specific higher-order descriptors, the bispectrum and trispectrum, as well as collapsed multi-point statistics derived from them, i.e. . We also compute quantities we call the , the Fourier transforms of the well-known cumulant correlators. We compute the redshift dependence of these objects and study their performance in the presence of realistic noise and photometric redshift errors.

Higher Order Statistics of the Galaxy Distribution

Author: Cristiano Sabiu

UCL

Co-Authors:

Session: COS: Cosmology and large scale structure

Presentation type: Talk

Summary:

Current spectroscopic galaxy surveys (eg SDSS) provides us with a map of large-scale over-densities in the Universe within a volume of ~1 (Gpc/h)^3. Future spectroscopic surveys like BigBOSS or photometric surveys like DES will push this volume even higher allowing us to determine for the first time the evolution of the higher-order clustering statistics with cosmic time. To make full use of these large data sets, it is important to accurately model the mapping between galaxies and the dark matter. Recently, this has been achieved using the "halo model" for how galaxies inhibit their dark matter halos. In this talk, I will present results of recent work on the Halo Model interpretation of SDSS Luminous Red Galaxies (LRGs) using 3-point statistics. I will also discuss current and future work, which includes Counts-In-Cells, Multifractal analysis and tests for Non-Gaussianity.

Models for the Clustering of Far-Infrared and Sub-millimetre selected Galaxies

Author: Jo Short

Cardiff University

Co-Authors: P. Coles (Cardiff University)

Session: COS: Cosmology and large scale structure

Presentation type: Talk

Summary:

Galaxy clustering is an important measure of the underlying dark matter distribution, which is itself key to understanding the formation of large scale structure. The two-point angular correlation function (Ï‰) is a commonly used metric to quantify this clustering. In this work we discuss and compare two alternative models for Ï‰ detected through the sub-millimetre emission using the Herschel Space Observatory. The first, Halo Model, method which represents the angular correlations as arising from one-halo and two-halo contributions, is flexible but complex and rather unwieldy. The second model is based on a much simpler approach: we incorporate a fitting function method to estimate the matter correlation function with approximate model of the bias inferred from the estimated redshift distribution. Both models are shown to give a good account of the shape of Ï‰ obtained from published preliminary studies of the HerMES survey performed using Herschel, and yield consistent estimates of the minimum halo mass within which the sub-millimetre galaxies must reside. We note also that both models predict an inflection in Ï‰ at intermediate angular scales, so the presence of the feature in the measured correlation function does not unambiguously indicate the presence of intra-halo correlations.

Large Scale Constraints on the Matter Power Spectrum from Peculiar Velocities

Author: Edward Macaulay

University of Oxford

Co-Authors: H. Feldman (University of Kansas); P. G. Ferreira (University of Oxford); M. J. Hudson (University of Waterloo, Universite Pierre et Marie Curie, Perimeter Institute for Theoretical Physics); R. Watkins (Willamette University)

Session: COS: Cosmology and large scale structure

Presentation type: Talk

Summary:

As an unbiased tracer of the large scale matter distribution, the peculiar velocities of galaxies are a powerful cosmological probe. The anomalously high dipole moment in the peculiar velocity field has appeared to be incompatible at the 2-sigma level with the current cosmological model. We have used the bulk flow of the peculiar velocity field to infer large scale constraints on the matter power spectrum. We have found that including higher moments of the velocity field dramatically increases the compatibility of the high bulk flow with the current cosmological model, and suggests a more specific, localized excess in the matter power spectrum at scales ~1 Gpc/h.

A Multiwavelength View of Star Formation Across Cosmic Time

Author: Alyssa Drake

Astrophysics Research Institute, LJMU

Co-Authors: C.A.Collins (LJMU); P.A.James (LJMU); C.J.Simpson (LJMU); I.K.Baldry (LJMU);

Session: COS: Cosmology and large scale structure

Presentation type: Poster

Summary:

Understanding the formation and evolution of galaxies relies heavily on the accurate determination of how when and where stars were formed. Tracing the evolution of the cosmic Star Formation Rate (SFR) is an essential tool for constraining galaxy formation and evolution models. The generally accepted view of hierarchical galaxy formation has been challenged in recent years by observations of â€œdownsizingâ€ in galaxies: star formation occurring earlier in more massive systems. Although this behaviour was first deemed to be anti-hierarchical, it has since been proved to be a natural part of the bottom up clustering process of Dark Matter (DM) halos. We aim to investigate the evolution of SFR as a function of environment and stellar mass using several narrow band filters. This way we can study a number of redshift slices spanning 10 Gyr, and start to place constraints on downsizing. The second half of the project will take several square degrees of data form VISTA to focus on examining the processes and mechanisms that trigger and halt star formation, and their evolution with cosmic time.

CBASS: a C-Band All Sky Survey

Author: Melis Irfan

JBCA, University of Manchster

Co-Authors: CBASS collaboration

Session: COS: Cosmology and large scale structure

Presentation type: Poster

Summary:

C-BASS, the C-Band All Sky Survey, is in its first phase of data capture. This 5GHz survey of sky intensity and polarisation will be a vital tool in the removal of polarised foregrounds from CMB data. C-BASS consists of a northern hemisphere telescope, situated at the Owens Valley Radio Observatory (OVRO) and a southern telescope in South Africa. Both C-BASS telescopes will produce moderate resolution (45' HPBW) maps, in both intensity and polarisation, of the Galactic synchrotron emission at 5 GHz. Not only will the maps provide polarised foreground measurements for component separation techniques; they shall also probe into the physics of the Galactic interstellar medium. At present, observations of the Northern sky are under way at OVRO, as well as development of techniques and software for astronomical calibration, atmospheric correction, and interactive data quality control and analysis. The first maps of the Northern sky are forthcoming. We will give an overview of the telescope set-up, its calibration and a display of its mapping capability. This will set the scene for the upcoming release of the northern C-BASS maps as well as the completion of the South African C-BASS telescope.

Vorticity in the Early Universe

Queen Mary, University of London

Co-Authors:

Session: COS: Cosmology and large scale structure

Presentation type: Poster

Summary:

Vorticity is ubiquitous in nature however, to date, studies of vorticity in cosmology and in the early universe have been quite rare. In this work we use the technique of cosmological perturbation theory to investigate vorticity in the early universe. At first, or linear order, we reproduce the standard result that vorticity decays with the expansion of the universe. However, the higher order theory exhibits a qualitative difference from the linear order theory, namely that different types of perturbation (classified as scalar, vector or tensor) do not decouple. We show that at second order vorticity is sourced by a term quadratic in linear order energy density and entropy perturbations. This is a generalisation of previous work which focused on barotropic fluids, and is an extension of Crocco's theorem from classical fluid dynamics to a cosmological setting.

Improving Dark Energy Figures of Merit in Future Galaxy Redshift Surveys

Author: Edward Macaulay

University of Oxford

Co-Authors:

Session: COS: Cosmology and large scale structure

Presentation type: Poster

Summary:

Galaxy redshift surveys have already placed strong constraints on alternatives to dark energy, in particular with the detection of baryon acoustic oscillations, and the measurement of the growth rate of cosmic structure. Forthcoming generations of surveys should improve these constraints further, and extend the measurements to higher redshifts. I will present results of Fisher matrix forecasts for such surveys, focusing on the effect of practical survey design considerations on dark energy figures of merit. I will include results on the effect of contamination due to redshift errors, and the choice of target redshift distributions to optimize cosmological constraints.

Multivariate observations go blind: how blind source separation provides new insight

Author: Thierry Dudok de Wit

Co-Authors:

Session: DAT: Solar and space data processing

Presentation type: Talk

Summary:

With recent satellite missions such as SDO, Themis and Cluster, large "multi" data sets (such as multi-wavelength images, or multi-point time series) have now become the standard in space science. Many space weather applications on the contrary require simple proxies that can be delivered in near real-time. To make the two meet, new data reduction techniques are needed. Here I'll explore the Blind Source Separation (BSS) approach, which consists in decomposing multivariate observations into a small set of elementary building blocks (or sources) that capture their salient features. This separation is said to be blind because the sources are extracted with the least prior information on them. BSS has recently become a very active field of research in several disciplines such as speech processing, remote sensing and chemometrics. Here weâ€™ll show how this novel concept can also provide new insight into the physics of the solar corona, using observations made by SDO/AIA, or in multipoint observations in the terrestrial magnetosphere. Depending on the physical assumptions, one may either combine such BSS techniques with multiscale (i.e. wavelet) decompositions, or impose constraints of positivity, using a Bayesian framework.

Analysis of electron spectra using artificial neural networks

Author: Chris Arridge

MSSL, University College London

Co-Authors: J. Gao (MSSL UCL); G.R. Lewis (MSSL UCL); A.J. Coates (MSSL UCL)

Session: DAT: Solar and space data processing

Presentation type: Talk

Summary:

Space plasma missions carrying electron analysers return large amounts of electron spectral data which requires careful analysis and processing. Much of this processing must often be performed by a human being due to the highly variable and sometimes nature of the data. This introduces a bottleneck into any data handling system which will only become more acute with the development of new missions, higher cadence data sets, and missions to the outer solar system requiring long interplanetary transfers. Statistical exploitation of large legacy datasets also suffers from these issues. In this talk we discuss the automated analysis of plasma electron measurements, taken by the CAPS/ELS sensor on the Cassini spacecraft, using artificial neural networks which mimic the behaviour of neurons in biological systems. Two applications will be highlighted: 1) the qualitative classification of spectra to identify bimodal distributions, and 2) the automatic determination of spacecraft potentials.

Automatic Background Subtraction Method for Use in Deriving Solar Flare Thermal Properties with GOES

Author: Daniel Ryan

Trinity College Dublin

Co-Authors: R.O. Milligan (NASA,GSFC/QUB); P.T. Gallagher (TCD); B.R. Dennis (NASA,GSFC); A.K. Tolbert (NASA,GSFC); R.A. Schwartz (NASA,GSFC); C.A. Young (NASA,GSFC)

Session: DAT: Solar and space data processing

Presentation type: Talk

Summary:

Since the mid-1970's, observations from the X-Ray Sensor (XRS) onboard the Geostationary Operational Environmental Satellite (GOES) have been used to derive the thermal properties of solar flares (temperature, emission measure etc.), making them ideal for conducting large-scale flare studies. However, the accurate determination of these properties strongly depends on the subtraction of background emission. Despite this, there is no widely accepted automatic background subtraction method for GOES observations, limiting the maximum size of any such study. In this talk we propose such a technique, the temperature and emission measure-based background subtraction (TEBBS), which employs improved versions of the background tests of Bornmann (1990). These tests determine whether a background subtraction preserves the expected rise in temperature and emission measure during a flare's impulsive phase. We ensure that temperature is always greater than the instrumental temperature limit (4MK) and employ the techniques of White et al. (2005) to directly analyse temperature and emission measure evolution during the rise phase. This method is compared with other candidate techniques for automatically addressing background emission. TEBBS is found to better preserve the expected temperature and emission measure behaviour of flares, making it ideal for use in large-scale studies of GOES flare observations.

Regularized Inversion of SDO and Hinode Differential Emission Measures

Author: Iain Hannah

University of Glasgow

Co-Authors: E. P. Kontar (University of Glasgow)

Session: DAT: Solar and space data processing

Presentation type: Talk

Summary:

Observations from SDO and Hinode provide an unprecedented view of plasma heating in the solar atmosphere. However, the inference of how much material is emitting at each temperature - the Differential Emission Measure DEM(T) - from this data is an ill-posed inverse problem. We present a model independent regularization algorithm used in RHESSI X-ray software for similar inversions making use of general constraints on the form of the DEM(T). The regularization produces error estimates on the calculated DEM(T) and provides a temperature resolution of the signal and method, thus giving a clear criteria to determine whether the plasma is consistent with isothermal model. The algorithm is also computationally fast making it ideal for the challenging amounts of SDO data. We demonstrate this technique applied to simulated SDO/AIA, Hinode/XRT and Hinode/EIS data and to recent coronal loop observations with SDO/AIA.

Recent Advances in 2D and 3D Solar Imaging

Author: Rami Qahwaji

Co-Authors: J. Zraqou, S. Hayajneh, T. Colak and S. Ipson

Session: DAT: Solar and space data processing

Presentation type: Talk

Summary:

We will introduce our latest Solar Imaging package, which is SolarStudio. Solar Studio can browse, locate and process the huge data sets generated by STEREO and SDO. New technologies were developed to automatically process multiple and overlapping images of the same scene to produce Super-Resolution (SR) images and videos. SolarStudio can also generate 3D Anaglyphs from uncalibrated pairs of SR images and it offers a number of other solar image processing tools. This presentation will also introduce our recent work on the 3D representation and modelling of solar features and loops. This new technology processes multi-wavelength SOHO/SDO images and solar catalogues to enable the creation of these 3D models. We will demonstrate some of the applications for this technology in the fields of visualisation, automated generation of 2D/3D synoptic maps, space weather, etc.

Using HELIO to address multi-spaceraft science use cases and the importance of CASSIS

Author: Robert Bentley

University Colege London

Co-Authors: M. Hapgood (STFC-RAL), J. Brooke (Univ. Manchester), P. Gallagher (Trinity College Dublin), S. Zharkov (UCL-MSSL), K. Benson (UCL-MSSL), V. Shetty (UCL-MSSL), C.H. Perry (STFC-RAL), P. Richards (STFC-RAL), A. le Blanc (Univ. Manchester), D. Fellows (Univ. Manchester), and the HELIO Team

Session: DAT: Solar and space data processing

Presentation type: Talk

Summary:

The Heliophysics Integrated Observatory, HELIO, is creating a collaborative environment where scientists can discover, understand and model the connection between solar phenomena, interplanetary disturbances and their effects on the planets. HELIO provides integrated access to metadata from observatories in the domains that constitute heliophysics in order to track the effects of solar phenomena as they propagate through interplanetary space and affect the planetary environments. It is designed around a service-oriented architecture with resources that support metadata search and curation, and data location, retrieval, processing and storage. We will report on the status of HELIO and describe the ways we would like to involve with the community through a series of Coordinated Data Analysis Workshops (CDAWs). In the CDAWs we able to demonstrate the capabilities of the project and participants will try to use them to address science use cases related to phenomena propagating from the Sun and observed in different parts of the inner Solar System. The first CDAW will take place in April 2011; two more will be held before the end of the project. We will also emphasize the importance of the CASSIS project in encouraging the interoperability necessary to undertake scientific studies spanning disciplinary boundaries.

Data integration and searching in Heliophysics

Author: John Brooke

University of Manchester

Co-Authors: A. LeBlanc (University of Manchester) D. Fellows (University of Manchester)

Session: DAT: Solar and space data processing

Presentation type: Talk

Summary:

Heliophysics is a new discipline that explores the Sun-Solar System Connection. Although the individual communities involved in heliophysics are well established, they have evolved independently and currently it is extremely difficult to find and compare data from across the diverse set of data archives and catalogues. We describe the use of methods derived from the Semantic Web to address this problem. We have integrated descriptions of data to develop an heliophysics domain ontology, which can be thought of as a controlled vocabulary enriched with rules that can be reasoned about by machines. This ontology is be used to map data from different instruments and different regions of the heliosphere. This includes an ontology for coordinate systems, which can express coordinate transformations required when searching data observed via different instruments. We drive the data integration via a workflow which accesses the data sources as Web Services. The workflows are created using Taverna (http://www.taverna.org) and can be run from a user interface that allowing the input of search terms. This enables searches that integrate data from catalogues describing solar activity observed from a variety of instruments and missions. This work is part of the HELIO project funded by the EU in the FP7 programme, see http://www.helio-vo.eu/

ESPAS: The near-Earth space data infrastructure for eScience

Author: Mike Hapgood

RAL Space

Co-Authors: Anna Belehaki (National Observatory of Athens, Greece)

Session: DAT: Solar and space data processing

Presentation type: Talk

Summary:

There is growing recognition around the world that scientists need better access to data on the near-Earth space environment (upper atmosphere, magnetosphere and upstream solar wind). This region is now recognised as a significant part of the environment that impacts on human activities through both space weather and solar effects on climate. Progress on these topics is a major intellectual challenge as it involves studies of highly coupled and often complex physical systems. Fortunately we now have a wealth of data from this region and thus the ability to test physical models that reflect that complexity. Unfortunately, that wealth of data is very diverse: a mix of remote sensing and in-situ sampling; sample locations that vary with time due to spacecraft motion and/or the rotation of the Earth; a range of data types from scalar to tensors and even more complex matrices. The ESPAS project, now under negotiation within the FP7 programme, seeks to exploit modern eScience methods to improve access to datasets from across near-Earth space and to integrate data with models of that environment. This presentation will outline on plans for ESPAS and in particular plans to engage both data providers and end users as ESPAS is developed.

A comparison of solar wind propagation delays derived from multi-spacecraft techniques

Author: Nathan Case

Lancaster University

Co-Authors: J. A. Wild (Lancaster University)

Session: DAT: Solar and space data processing

Presentation type: Talk

Summary:

We present a large-scale statistical study of the solar wind propagation delay between NASAâ€™s Advanced Composition Explorer (ACE) spacecraft and ESAâ€™s Cluster-1 spacecraft. This study focuses on those periods when Cluster was within the unimpeded solar wind, upstream of the bow shock nose, between seasons 2001 and 2010. Using a cross correlation method to compare the ACE and Cluster data, over 8600 propagation delays are calculated and compared to the OMNIweb dataset and a flat propagation model. The results show that, on a statistical scale, there is little difference between the OMNI and flat propagation delay times and that the cross correlation method agrees well with both. The influence of the solar wind speed and IMF orientation on the relationship between the estimated and observed solar wind propagation delays will also be explored.

Study of Anisotropic Turbulence using the Undecimated Discrete Wavelet Transform

Author: Khurom Kiyani

Imperial College London

Co-Authors: O. Fauvarque (Ecole Normale Superior, France; Imperial College London, UK); S. C. Chapman (University of Warwick, UK)

Session: DAT: Solar and space data processing

Presentation type: Poster

Summary:

In-situ spacecraft measurements of the solar wind at 1AU show a highly turbulent plasma with a spatio-temporal structure consisting of a large continuous range of scales. This multi-scale nature is exhibited by a broad-band power spectral density spanning several decades from scales of the order of solar structures to the electron Larmor radius. The nature of the magnetic fluctuations in such a medium is highly anisotropic; with fluctuations being ordered parallel and transverse to the 'background' magnetic field. However, with no clear separation of scales the traditional distinction between a background field and the fluctuations is no longer apparent. In this poster we show that the Undecimated Discrete Wavelet Transform (UDWT) is not only a natural way of defining a local scale-dependent background field and fluctuations self-consistently; it also possesses additional benefits such as the retention of event information, spectral completeness and importantly fast computation amongst other things. We will illustrate the use of the UDWT by presenting some key statistics in the analysis of anisotropic turbulence, as applied to high-cadence magnetic field measurements from the Cluster spacecraft.

Web-Based Data Processing System for Automated Detection of Oscillations

Author: Valery Nakariakov

University of Warwick

Co-Authors: R. Sych (NAOC, Beijing, China and ISTP, Irkutsk, Russia), S.A. Anfinogentov (ISTP, Irkutsk, Russia)

Session: DAT: Solar and space data processing

Presentation type: Poster

Summary:

A web-based, interactive system for the remote processing of imaging data sets (i.e., EUV, X-ray, and microwave) and the automated interactive detection of wave and oscillatory phenomena in the solar atmosphere is presented. The system targets localised, but spatially resolved, phenomena such as kink, sausage, and longitudinal propagating and standing waves. The system implements the methods of Periodmapping for pre-analysis, and Pixelised Wavelet Filtering for detailed analysis of the imaging data cubes. The system is implemented on the dedicated data-processing server http://pwf.iszf.irk.ru, which is situated at the Institute of Solar-Terrestrial Physics, Irkutsk, Russia. Input data in the .sav, .fits, or .txt formats can be submitted via the local and/or global network (the Internet). The output data can be in the png, jpeg, and binary formats, on the userâ€™s request. The output data are periodmaps; narrowband amplitude, power, phase and correlation maps of the waveâ€™s sources at significant harmonics and in the chosen spectral intervals, and mpeg movies of their evolution. The system's performance is illustrated by its application to the analysis of 3-min oscillations above sunspots, observed with SDO/AIA and NoRH.

Isolating CME signal in coronagraph images

Author: Huw Morgan

Institute for Astronomy, University of Hawaii

Co-Authors: J. Byrne (Institute for Astronomy, University of Hawaii)

Session: DAT: Solar and space data processing

Presentation type: Poster

Summary:

A deconvolution method is used to separate LASCO C2/C3 images into dynamic and quiescent components. The large set of dynamic images collected over 14 year contain all observed CMEs of all sizes. We describe how this wealth of information can be further reduced and the possibilities for statistical analysis. In particular, wavelet edge detection techniques enable the structural categorization of CMEs.

Turbulent characteristics of the intensity ï¬‚uctuations in the Hinode/SOT images of a solar QP

Author: ERSILIA LEONARDIS

UNIVERSITY OF WARWICK

Co-Authors: S.C. Chapman (University of Warwick); C. Foullon (University of Warwick)

Session: DAT: Solar and space data processing

Presentation type: Poster

Summary:

The Solar Optical Telescope (SOT) on board the Hinode spacecraft provides long time intervals of observation of the solar corona via images at simultaneous high spatial and temporal resolution. We focus on speciï¬c Calcium II H-line observations of a solar Quiescent Prominence (QP) which exhibits several small scale up-ï¬‚ows with very highly variable dynamics suggestive of turbulence. Fluctuations of bulk quantities associated with a turbulent ï¬eld show similarity in their non-Gaussian statistics leading to the following scaling for the pth moment of the structure functions: Sp(Î´)=<|f(x+Î´)âˆ’f(x)|^p>âˆ¼ Î´^Î¶(p), where Î´ is an observational scale and Î¶(p) are the scaling exponents. Recently, a generalization of this scaling has been found for turbulent systems of ï¬nite size - i.e. in the quiet solar wind - which instead exhibit a single robust scaling function g(Î´/Î´0) such that Sp(Î´)âˆ¼Sp(Î´0)g(Î´/Î´0)^Î¶(p), where Î´0 is some characteristic parameter of the ï¬‚ow. We test this generalized scaling by performing statistical analyses such as Generalized Structure Function (GSF) and Extended-Self Similarity (ESS) on the intensity ï¬‚uctuations of the prominence. We verify the non-Gaussian nature of the spatial ï¬‚uctuations and, consistently with a turbulent ï¬‚ow of ï¬nite size, we ï¬nd evidence of ESS along the directions either longitudinal and transverse to the bulk (driving) ï¬‚ow.

On the Multi-spacecraft Determination of Periodic Surface Wave Phase Speeds and Wavelengths

Author: Claire Foullon

University of Warwick

Co-Authors: C.J. Farrugia (UNH, USA), A.N. Fazakerley (MSSL/UCL, UK), C.J. Owen (MSSL/UCL, UK), F.T. Gratton (CONICET/UBA, Argentina), R.B. Torbert (UNH, USA)

Session: DAT: Solar and space data processing

Presentation type: Poster

Summary:

Observations of surface waves on the magnetopause indicate a wide range of phase velocities and wavelengths. Their multi-spacecraft analysis allows a more precise determination of wave characteristics than ever before and reveal that approximations, which take a predetermined fraction of the magnetosheath speed or the average flow velocity in the boundary layer, can overestimate phase speeds. We show that time-lags between two or more spacecraft can give a qualitative upper estimate, and we confirm the unreliability of flow approximations often used by analysis of a few cases. Using two-point distant magnetic field observations and spectral analysis of the tailward magnetic field component, we propose an alternative method to estimate the wavelength and phase speed at a single spacecraft from a statistical fit at the other site.

2-D Time-frequency analysis of phase coherence of solar wind turbulence

Author: Olivier Fauvarque

Ecole Normale Superior, Imperial College London

Co-Authors: F. Sahraoui (LPP/CNRS-Ecole Polytechnique-UPMC)

Session: DAT: Solar and space data processing

Presentation type: Poster

Summary:

Several observations in space plasmas have reported the presence of coherent structures at different plasma scales. Structure formation is believed to be a direct consequence of nonlinear interactions between plasma modes that depend strongly on the phase synchronization of those modes. Analysing directly Fourier phases is however very tricky due to their dependence on an arbitrary time origin and to their 2Ï€ periodicity (which makes the phases appear completely mixed/random, even when they are not!). A method, based on Surrogate data, has been developed recently to solve this problem and to allow one to systematically detect coherent structures in turbulent signals [Sahraoui, PRE, 2008]. This 1-D method, however, suffers the weakness that is it can estimate the scale of the structures but only over the whole used time series. Here we present a new version of the method that makes a 2-D analysis of the time series, i.e., in the time and the scale (frequency) domains. This makes possible to estimate the size of the structures and to localize them in time. After validating the new method on synthetic data, we will show applications to the Cluster data. In particular, we will present recent results on coherent structures at small/electron scales in the solar wind. A discussion of the consequence of such observations on theoretical modeling of solar wind turbulence (e.g., weak versus strong, intermittency) will be discussed.

Feature detection algorithms in HELIO

Author: David Perez-Suarez

Trinity College Dublin

Co-Authors: P. Higgins (TCD); L.D. Krista (TCD); P.T. Gallagher (TCD); N. Fuller (Paris Observatory[obspm]); X. Bonnin (OBSPM); J. Aboudarham (OBSPM); C. ReniÃ© (OBSPM); G. Pierantoni (TCD)

Session: DAT: Solar and space data processing

Presentation type: Poster

Summary:

The HELiophysics Integrated Observatory (HELIO; www.helio-vo.eu) is an advanced software system, funded under FP7 e-Infrastructures, that provides a set of data search and retrieval services to study the heliosphere. One of primary services is the HELIO Feature Catalogue (HFC) which provides access to a complete catalogue of automatically detected features in the heliosphere. The detection algorithms will not only be used to populate the HFC, but will form part of the service allowing users to run jobs on different data or with different parameters on the grid computing facilities provided by Grid-Ireland (www.grid.ie). Here, we describe the detection algorithms of the first features implemented on the HFC (Filaments, Active Regions, Coronal Holes and Sunspots) and how they are being used within HELIO.

The Hilbert-Huang transform: a new approach for studying quasi-periodic pulsations in solar flares

Author: Jennifer (Harris) Hershaw

University of Warwick

Co-Authors: A.R.Inglis (NASA Goddard Space Flight Center); V.M.Nakariakov (University of Warwick, Pulkovo Observatory)

Session: DAT: Solar and space data processing

Presentation type: Poster

Summary:

Flaring energy releases are rapidly evolving and generally short-lived processes, often exhibiting anharmonic oscillations, and this should be taken into account in their analysis. We test the applicability of the Hilbert-Huang transform method, which was specifically designed to work for nonstationary and nonlinear data, to the analysis of oscillatory flaring light curves. Both synthetic and natural datasets are analysed using empirical mode decomposition with the Hilbert transform, and the results are compared against Morlet wavelet analysis.

Author: Alison Laird

University of York

Co-Authors: for the TUDA and DRAGON collaborations

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

In explosive astrophysical environments such as novae, X-ray bursts and supernovae, radioactive nuclei can play a key role in energy generation and nucleosynthesis. In novae, due to the relatively low peak temperatures achieved, nuclear processing is limited to low mass isotopes (A < 40). Consequently only a limited number of nuclear reactions are important, and the availability of new and intense beams of radioactive nuclei has allowed many of these reactions to be studied. The current status of measured novae reaction rates will be outlined and recent results presented of the lowest energy direct measurement to date of the 18F(p,a)15O reaction. This reaction is critical in determining the final abundance of 18F produced during a nova outburst. By understanding the amount of 18F in the ejecta, observations of the 511 keV gamma-rays from its decay can provide unique information about the conditions during the nova.

Radio observations of the gamma-ray nova V407 Cyg

Author: Tim OBrien

University of Manchester

Co-Authors:

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

The symbiotic nova V407 Cyg outburst in March 2010. It was detected as a transient source by Fermi making it the first gamma-ray nova. I will report on radio observations of V407 Cyg with MERLIN, VLBI and VLA. I will discuss the interpretation of these observations in the context of emission from shock interactions of the ejecta and flash-ionization of the circumstellar medium.

Novae Light Curves from the Solar Mass Ejection Imager (SMEI)

Author: Rebekah Hounsell

Liverpool John Moores University

Co-Authors: M. F. Bode(Liverpool John Moores University); P. P. Hick, A. Buffington, B. V. Jackson, J. M. Clover (University of California San Diego/Center of Astrophysics and Space Science); A. W. Shafter (San Diego State University); M. J. Darnley, D. Harman, I. Steele, N. Mawson (Liverpool John Moores University) A. Evans (Astronomy Group, School of Physical and Geographical Sciences, Keele University); S.P.S. Eyres (Center for Astrophysics, University of Central Lancashire); T.J. O'Brien (Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester)

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

We present light curves of three classical novae (KT Eridani, V598 Puppis, V1280 Scorpii) and one recurrent nova (RS Ophiuchi) obtained by the Solar Mass Ejection Imager (SMEI) on board the Coriolis solar satellite. SMEI provides near complete sky-map coverage with precision visible-light photometry at 102-minute cadence. These unparalleled light curves allow us to explore the fundamental parameters of individual novae including the epoch of the initial explosion, the reality and duration of any pre-maximum halt (found for all fast novae in our sample), the presence of secondary maxima, speed of decline of the initial light curve, plus precise timing of the onset of dust formation. It is also noted that two of the four novae we have detected (V598 Pup and KT Eri) were only discovered by ground-based observers weeks or months after maximum light, yet these novae reached peak magnitudes of 3.46 and 5.42 respectively. This emphasizes the fact that many bright novae per year are still overlooked, particularly those of the very fast speed class. Work is now continuing on the full SMEI dataset and initial results of the search for previously undiscovered novae will be presented.

Swift and SMARTS observations of the Recurrent Nova LMC 2009a (= LMC 1971b)

Author: M.F. Bode

Liverpool JMU

Co-Authors: A.P. Beardmore, J.P. Osborne, K.L. Page (Leicester), F.M. Walter (Stony Brook), G. Schwarz (AAS), M.J. Darnley (LJMU), J-U. Ness (ESA), A. Evans (Keele), T.J. O'Brien (Manchester), S.P.S. Eyres (Central Lancs) and the Swift Nova-CV Group

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

Nova LMC 2009a is coincident with the position of LMC 1971b and thus is confirmed as a Recurrent Nova. Extensive optical and near-IR photometry are reported together with UV and X-ray observations using the Swift satellite. Expansion velocities between 1000 and 4000 km/s are implied from optical lines. The strengthening of the HeII 4686A line precedes the emergence of the Super-Soft Source (SSS) in X-rays at t ~ 63 - 70 days. The SSS is initially highly variable. Periodic oscillations with P = 1.19 days are found in the UV and optical data from day 43 onwards and are subsequently evident in the SSS. We associate these oscillations with the binary period. The UV/optical oscillations however lead those in the X-ray by 0.24 days. The progenitor system has been identified and the amplitude of the outburst (A ~ 9 mags) is anomalously low if the object were such a fast Classical Nova. From the evolution of the SSS, we determine a WD mass between 1.1 and 1.3 M_sun. We then derive a very high accretion rate onto the WD surface which is consistent with the low outburst amplitude and position of the progenitor on a colour-magnitude diagram. Comparison with published models suggests that a high rate of accretion is also required to give rise to the 38 year inter-outburst interval on a WD of the mass we derive. Finally, we note striking similarities between LMC 2009a and the Galactic nova KT Eri (2009).

An Infrared and Optical, Spectroscopic and Photometric, Survey of Novae in M31.

Author: Matt Darnley

Liverpool John Moores University

Co-Authors: Allen Shafter (SDSU, USA), Mike Bode (LJMU)

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

We present the results of a multi-year optical spectroscopic and photometric survey of novae in M31. Our survey resulted in a total of 53 spectra of 48 individual nova candidates. These data double the number of spectra extant for novae in M31 through the end of 2009 and bring to 91 the number of M31 novae with known spectroscopic classifications. We find no compelling evidence that spectroscopic class depends sensitively on spatial position or population within M31 (i.e., bulge vs. disk), although the distribution for He/N systems appears slightly more extended than that for the Fe II class. In addition, we find a weak dependence of nova speed class on position in M31, with the spatial distribution of the fastest novae being slightly more extended than that of slower novae. We also report the results of the first infrared survey of novae in M31. Both photometric and spectroscopic observations of a sample of 10 novae were obtained with the Spitzer Space Telescope. The observations revealed evidence for dust formation in two of the novae, and [Ne II] 12.8 Î¼m line emission in a third.

The Discovery and evolution of an unusual new radio source in M82

Author: Rob Beswick

JBCA University of Manchester

Co-Authors: T. W. B. Muxlow (JBCA), S. T. Garrington (JBO/JBCA), M. Gendre (JBCA) D. Fenech (UCL), M. Argo (Curtin, Aus), A. Brunthaler (MPIfR)

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

Within the central region of M82 over 50 compact radio sources have been discovered. These sources have been identi ed as either radio supernova ( 2/3 of sources) or Hii regions (remaining 1/3), confirming the high levels of recent star-formation underway in tis galaxy. However despite very regular radio monitoring of M82 over the last 4 or more decades only a very small number of new or 'transient' sources have ever been identi ed. Most notable of these was the detection of the bright new radio supernova SN2008iz. Following the initial announcement of the detection SN2008iz we undertook an increased level of high resolution radio monitoring or M82. The aim of this renewed campaign was to track the early time flux evolution of SN2008iz and the other compact sources in M82, however serendipitously this also resulted in the detection of a second faint (~1 mJy) new radio source. These monitoring observations were able to constrain the appearance of this new source to with just a few days and have subsequently tracked its flux density and structural evolution along with it's potential proper motion (~4c) over a period of a year. In this talk I will describe the discovery of this new source, its potential physical nature and present some of the first e-MERLIN observations of M82.

The double-peaked 2008 outburst of the accreting milli-second X-ray pulsar, IGR J00291+5934

Author: Fraser Lewis

Faulkes Telescope Project / University of Glamorgan

Co-Authors: D.M. Russell (University of Amsterdam)

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

We present data from a rare â€˜double-peakedâ€™ outburst of the accreting milli-second X-ray pulsar (AMXP), IGR J00291+5934, The data comprise optical photometry from Faulkes Telescope North and the Isaac Newton Telescope, Keck Telescope spectroscopy, infrared photometry from PAIRITEL, UV photometry from Swift UVOT, radio data from the Westerbork Synthesis Radio Telescope and X-ray data from the Swift, XMM-Newton and RXTE X-ray missions. We show the light curve morphology, presenting the first radio-X-ray Spectral Energy Distributions (SEDs) for this source and the most detailed UV-IR SEDs for any outbursting AMXP. The outburst morphology is unusual for an AMXP, comprising two peaks, the second containing a â€˜plateauâ€™ phase of ~10 days at maximum brightness within 30 days of the initial activity. In the optical, the SEDs contain a blue component, indicative of an irradiated disc, and a transient near-infrared (NIR) excess. This excess is consistent with a simple model of an optically thick synchrotron jet (as seen in other outbursting AMXPs), however we discuss other potential origins. These results are presented within the wider context of an extensive optical monitoring program of 32 Low-Mass X-ray Binaries using the 2-metre Faulkes Telescopes in Hawaii and Australia.

What to do with sparkers?

Author: Evan Keane

Co-Authors:

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

In 2007, the discovery of the so-called Lorimer Burst' was announced, a 5-ms duration radio pulse originating from an apparently cosmological distance. The physical origin of this sparker' has seen much debate so that there are now two explanations favoured by the community, i.e. that the source is either truly astrophysical, or that it is some terrestrial signal generated either in the Earth's atmosphere or human-generated radio interference. Here I will review the evidence for and against the interpretation of this burst as astrophysical. I will also describe a new discovery of a sparker, identified in a search of archival data from the Parkes Telescope. This new source obeys the theoretical frequency dispersion law, is dispersed at a completely different value to the original burst, and by all measures appears a genuine astrophysical burst. The only question seems to be how distant it is, and I will discuss the means for estimating this and their problems. I will also ask what can be done with such sparkers to further investigate the nature of their origins, something which must be considered in the era of all-sky transient monitoring which we are now entering with LOFAR and the SKA.

Fermi and the Sequence: gamma-ray production efficiencies in blazars.

Author: Jennifer Gupta

Jodrell Bank Centre for Astrophysics

Co-Authors: I. W. A. Browne (Jodrell Bank Centre for Astrophysics); M. W. Peel (Jodrell Bank Centre for Astrophysics)

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

The Fermi-LAT survey has dramatically increased the number of gamma-ray blazars known and means that for the first time, a large sample of blazars selected by the strength of their gamma-ray emission exists. We have cross-identified the blazars listed in the first Fermi-LAT catalog (1FGL) with the CRATES radio catalog. Using the 8.4 GHz flux density as a proxy for the jet power, we have computed Compton efficiencies, a measure of the ability of the jet to convert the power in the ultrarelativistic jet electrons into gamma-rays through the inverse Compton process. We have compared the Compton efficiencies of the two blazar subsets, BL Lacs and FSRQs, and find no evidence for different mean Compton efficiencies between the two classes, contrary to what might be expected from the blazar sequence. In addition to this, we also investigate the relationship between Compton efficiency and absolute magnitude within the FSRQs and find no correlation.

Space densities of AGN and the FR dichotomy

Author: Melanie Gendre

JBCA

Co-Authors: J.V. Wall (U.B.C.), P.N. Best (ROE/IfA)

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

Extended double-lobe radio sources can be morphologically classified into two groups: Fanaroff-Riley (FR) type I sources have the highest surface brightness along the jets near the core and FR type II sources show the highest surface brightness at the lobe extremities, as well as more collimated jets. This thesis work focuses on a comparison of the space densities of FRI and FRII sources at different epochs, with a particular focus on FRI sources. The Combined NVSS-FIRST Galaxy catalogue (CoNFIG), a sample of radio sources at 1.4 GHz, includes VLA observations, FRI/FRII morphology classifications, optical identifications and redshift estimates. The final catalogue consists of 858 sources over 4 samples (CoNFIG-1, 2, 3 and 4 with flux density limits of S_1.4GHz = 1.3, 0.8, 0.2 and 0.05 Jy respectively). It is 95.7% complete in radio morphology classification and 74.3% of the sources have redshift data. Combining CoNFIG with complementary samples, the distribution and cosmic evolution of FRI and FRII sources are investigated. It is found that FRI sources undergo mild evolution and that, at the same radio luminosity, FRI and FRII sources show similar space density enhancements in various redshift ranges, implying a common mechanism powering the luminosity-dependent evolution. This improved understanding of radio galaxy evolution will also give better insight into the the physics of AGN and their role in galaxy formation.

Measuring the Kinetic Luminosity Functions of Powerful FRII Radio Galaxies

Author: Anna Kapinska

School of Physics & Astronomy, University of Southampton

Co-Authors: P.Uttley (School of Physics & Astronomy, University of Southampton) C.R.Kaiser

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

FRII radio galaxies are relatively simple systems which can be used to determine the influence of jets on their environments. Even simple analytical models of FRII evolution can link the observed lobe luminosities and sizes to fundamental properties such as jet power and density of the ambient medium; these are crucial for understanding AGN feedback. However, due to strong flux selection effects interpreting FRII samples is not straightforward. To overcome this problem we construct Monte Carlo simulations to create artificial samples of radio galaxies. We explore jet power and external density distributions by using them as the simulation input parameters. Further, we compute radio luminosity functions (RLFs) and fit them to the observed low-frequency radio data that cover redshifts up to z ~ 2, which gives us the most plausible distributions of FRIIs' intrinsic and extrinsic properties. Moreover, based on these RLFs, we obtain the kinetic luminosity functions (KLFs) of these powerful sources.

The long-term optical polarization variability of the BL Lac object PKS 2155-304

Author: Nicolette Pekeur

Durham University

Co-Authors: Dr. S.B. Potter (South African Astronomical Observatory); Dr. P.M. Chadwick (Durham University); Dr. M. Daniel (Durham University)

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

The polarization provides a direct means of disentangling the thermal emission of blazars from the synchrotron emission at optical wavelengths. In this work we present the optical polarization light curve of the high-frequency peaked blazar PKS 2155-304 during 2009 and 2010 when the source experienced both active and quiescent periods. Measurements were obtained with the HIgh Speed Photo-POlarimeter (HIPPO) of the South African Astronomical Observatory as part of an ongoing observation campaign of the source. Complementary observations from the Steward Observatory blazar monitoring program are also presented. The optical polarization variability is then compared to simultaneous gamma-ray measurements as recorded by the Fermi satellite allowing us to probe both the low and high energy peaks of the source's spectral energy distribution.

Broad emission lines and active black holes

Author: Stephen Fine

Durham University

Co-Authors: T. Shanks S. Croom

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

Recent surveys have produced >150,000 spectra of QSOs making them an exceptional tool for observational cosmology. Given single-epoch virial SMBH mass estimators it is now possible to estimate the super-massive black hole mass of many thousands of accreting objects between z~0. and 4.5. The prodigious size of modern surveys necessitates novel automated analysis techniques and many large scale analyses can be found in the literature. I will discuss an analysis of the MgII and CIV lines in spectra taken from three of the largest current surveys of QSOs. The results are used to make inferences about the population of active black holes, and their evolution from z~4.5 to 0.5. Our results are compared to predictions from semi analytic models and we find excellent agreement in general. However, we also find that there are inconsistencies between our results using the MgII and CIV lines. This may point to problems with the way black hole masses are estimated and I will discuss the implications for black hole mass estimation in the high redshift Universe.

Extreme X-ray luminosity star-forming galaxies: extraodrinary starbursts, or AGN?

Author: Floyd E. Jackson

Departmane of Physics, Durham University

Co-Authors: Timothy P. Roberts (Department of Physics, Durham University); Jonathan M. Gelbord (Astronomy & Astrophysics, Eberly College of Science, Pennsylvania State University); Martin J. Ward (Department of Physics, Durham University); Julie L. Wardlow (Department of Physics & Astronomy, University of California); David M. Alexander (Department of Physics, Durham University); Mike G. Watson (X-ray & Observational Astronomy Group, Department of Physics & Astronomy, University of Leceister)

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

Surveys have revealed a class of object displaying both high X-ray luminosities (L$_$ $>$ 10$^$ erg s$^$), and a lack of a discernible active galactic nucleus (AGN) in the optical band. If these sources are powered by star formation activity alone, they would be the most extreme X-ray luminosity star-forming galaxies known. We have investigated the mechanism driving the X-ray luminosities of such galaxies by studying the X-ray emission of three mid redshift (z $\sim$ 0.1) examples of this class, selected from a cross-correlation of the SDSS DR5 and 2XMMp DR0 catalogues. X-ray spatial and long-term variability diagnostics of these sources suggest that they are compact X-ray emitters. This result is supported by the detection of rapid short term variability in an observation of one of the sources. The spectra of all three sources are best fitted with a simple absorbed power-law model, thus betraying no significant signs of star formation. These results indicate that the X-ray emission is powered by AGN activity. But why do these sources not display optical AGN signatures? We show that the most likely explanation is that the optical AGN emission lines are being diluted by star formation signatures from within their host galaxies.

King charlesâ€™ star: a multidisciplinary approach to dating the supernova known as Cassiopeia A

Author: Martin Lunn MBE

Yorkshire Museum

Co-Authors: Lila Rakoczy Independent Scholar

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

Few astronomical phenomena have been as studied as the supernova known as Cassiopeia A. Widely believed to have occurred in the latter half of the seventeenth century, it is also thought to have gone unrecorded. This paper will argue that Cas A did not go unobserved, but in fact was seen in Britain on May 29, 1630, and coincided with the birth of the future King Charles II of Great Britain. This â€˜noon-day starâ€™ is an important feature of Stuart/Restoration propaganda, the significance of which has been widely acknowledged by historians and literary experts. The argument here, however, is that in addition the historical accounts provide credible evidence for a genuine astronomical event, the nature of which must be explained. Combining documentary analysis with an overview of the current scientific thinking on dating supernova, the authors put forward their case for why Charlesâ€™ star should be recognized as a sighting of Cas A. Finally, it will be argued that a collaborative approach between the humanities and the sciences can be a valuable tool, not just in furthering our understanding of Cas A, but in the dating of supernovae in general.

New supernova discoveries with the Palomar Transient Factory

Author: Kate Maguire

Oxford

Co-Authors: M. Sullivan (Oxford), P. Nugent (LBNL), D. A. Howell (LCOGT/UCSB), and the PTF collaboration.

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

The Palomar Transient Factory (PTF) is an optical wide-angle, rolling-search sky survey, which is designed to search for transient events and variable sources. It has the ability to rapidly detect new transient objects and schedule them for photometric and spectroscopic follow-up observations. In this talk, I will describe some of the most recent supernova events discovered by PTF. These include unusual and interesting classes of supernovae that have not been discovered to date in previous surveys and that challenge our current understanding of SN theory.

STILT (Small Telescopes Installed at LT) instruments

Author: Neil Mawson

Astrophysics Research Institute JMU

Co-Authors: I.A.Steele (ARI JMU)

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

STILT is a set of three wide imaging setups that have the ability to observe thousands of objects in just a single image. The current setup includes: an all sky camera, which is capable of imaging to 6th magnitude which shows it is capable of detecting some bright transient events. A 20 degree field of view camera, which with its wide field and the ability to image to ~12th magnitude can observe around 5000 stars in a single image and a 1 degree field of view telescope, which is capable of reaching 18th magnitude. The camera's are situated at the Liverpool Telescope on La Palma. All three setups carry out 10 second exposures every minute the LT enclosure is open, so provide high time resolution data. The aim is to create a data pipeline, which will automatically reduce the data and catalogue the objects in each image. Then cross check with a current database and create an alert for any detected object which the system believes to be of stellar origin and previously uncatalogued. So far the STILT system is already contributing to the analysis of both a GRB and a two novae.

Evidence for a varying IMF using CC SNe populations

Author: Stacey Habergham

Astrophysics Research Institute, LJMU

Co-Authors: J.P.Anderson (Departamento de Astronomia, Universidad de Chile) P.A.James (Astrophysics Research Institute, LJMU)

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

The universality of the initial mass function (IMF) has been hotly debated over recent history. The Bastian et al. review (2010) concludes that evidence for variations is as yet unreliable, with most claims being based on unresolved stellar systems. Using the observed ratios of the various sub-types of core-collapse supernovae (CC SNe), which have different mass progenitors, one can constrain the high-mass end of the IMF in various environments. We have performed a recent analysis of the CC SNe distribution in disturbed and undisturbed galaxies in the local universe and found a remarkable excess of those supernovae thought to have the most massive progenitors, in the central regions of disturbed systems. This excess has been attributed to a 'top-heavy' initial mass function in these regions. Here we will discuss the reasons behind this interpretation, alternative explanations and future observations to test the resulting hypotheses.

Transients with the Gaia mission

Author: Vasily Belokurov

Institute of Astronomy, University of Cambridge

Co-Authors:

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

Gaia is a successor to the Hipparcos mission with a main goal of measuring positions, distances and velocities for stars from almost the entire Galaxy. In its 5 year life-time (starting in 2013), Gaia will repeatedly scan the entire sky down to about 20th magnitude. The Gaia Science Alerts system, based at the Institute of Astronomy, Cambridge University, will use the daily data stream from the spacecraft to look for and report on transient phenomena. The data stream will be processed in near real-time in order to provide rapid alerts to facilitate ground-based follow-up. Objects of interest include supernovae, microlensing events, GRB afterglows, M-dwarf flares, R CrB-type stars, classical and recurrent novae and unknown transients. The talk will provide an overview of the Gaia alerting system and highlight the data processing challenges from detection to event classification and publication.

Optical Polarization as a probe of GRB magnetic fields

Author: Iain Steele

Liverpool John Moores University

Co-Authors:

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

An important probe of the configuration of the magnetic field in GRBs may be obtained through optical polarimetry. We have built a series of instruments to address this problem on the Liverpool Telescope. I shall describe how results of our RINGO observations of GRB060418 and GRB090102 may be understood in terms of a possible unified model for GRB magetization. I shall also present the latest results from our new polarimeter (RINGO2) which has observed 3 more bursts to date.

Polarization in Early GRB Afterglows

Author: Richard Harrison

Astrophysics Research Institute LJMU

Co-Authors:

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

The recent detection of ten percent polarization of an optical afterglow just 160 sec after the explosion of GRB 090102 opens the new exciting possibility of directly measuring the magnetic properties of gamma-ray burst (GRB) jets. A new generation of polarimeters, including RINGO2 on the Liverpool telescope, allow the detection of a larger number of fainter bursts and, for the first time, measure the temporal evolution of the polarization degree and position angle of early optical afterglow. We examine several polarization scenarios, and we discuss how early polarimetery provides constrains on the energy content and geometry of the relativistic ejecta from GRB central engine.

Itâ€™s TOUGH at all redshifts: the redshift distribution of The Optically Unbiased GRB Host sample

Author: Bob Chapman

University of Iceland / University of Hertfordshire

Co-Authors:

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

The Optically Unbiased GRB Host (TOUGH) sample presents galaxy information for a homogeneous sample of the hosts of 68 Swift long GRBs observed by the VLT between 2006 and 2009. This sample has an unprecedented completeness in redshift data of 71%, and here we present the redshift distribution with an emphasis on comparing the observed distribution with that obtained from GRB luminosity function modelling. With long GRBs known to be associated with the deaths of massive stars, their intrinsic rate can be assumed to follow the Star Formation Rate (SFR) history of the Universe, albeit with possible modifications for (e.g.) metallicity effects. The mean redshift of the sample is found to be = 2.12, and we can place conservative limits on the fraction of Swift GRBs at high z to be a maximum of 13% (3%) at z>6 (z>7). Although good fits to the observed Swift flux distribution (logN-logS) can be found under a variety of cosmic SFR parameterisations, comparison of the resultant redshift distributions with the TOUGH sample implies that the GRB rate density, and hence cosmic SFR, appears to be rather higher at z>2 than would be suggested by other indicators of high redshift star formation rates.

The SVOM gamma-ray burst mission

Author: Julian Osborne

University of Leicester

Co-Authors: Jaques Paul (CEA), Bertrand Cordier (CEA), Diego Gotz (CEA), George Fraser (Leicester), Adrian Martindale (Leicester), Paul O'Brien (Leicester), Phil Evans (Leicester), Andy Beardmore (Leicester).

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

SVOM is a French-Chinese gamma-ray burst satellite due for launch in 2016. It is expected to detect ~80 GRBs/yr, a similar rate to that seen by Swift. Bursts will be detected and located by the coded-mask ECLAIRs instrument in the 4-80 keV band (with sensitivity to 250 keV), supplemented by the GRM: a pair of non-imaging spectrometers working at 50 keV - 5 MeV. Rapid slewing of the spacecraft will allow afterglows to be located and characterised with high precision in the X-ray and optical bands using the MXT and the VT telescopes at 0.3-6 keV and 400-1000 nm respectively. The novel Microchannel X-ray Telescope design (PI: Fraser @ Leicester) will be based on the ESA BeppiColumbo MIXS-T instrument which will be used to view the surface of Mercury in flourescent X-rays. I will describe the performance of the SVOM system, which will secure the detection of short and long GRBs during the Advanced LIGO era.

The onset and physics of the X-ray afterglow in Gamma Ray Bursts.

Author: Phil Evans

University of Leicester

Co-Authors: R. Willingale (U. Leicester), J.P. Osborne (U. Leicester), P.T. O'Brien (U. Leicester)

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Talk

Summary:

We use the recently developed Swift Burst Analyser to study the onset of the X-ray afterglow in Gamma Ray Bursts. The Burst Analyser automatically creates flux lightcurves of Swift-BAT and XRT data, accounting for spectral evolution as the GRB progresses. In some GRBs the X-ray spectrum evolves strongly around the time that the light curve shows a flattening behaviour; a phenomenon which manifests itself as a light curve feature suggestive of the onset of the X-ray afterglow. We propose the hardness and flux evolution during this transition is the result of the combined effects of a decaying and spectrally evolving prompt component plus a spectral invariant rising afterglow component, and fit such a model. Our fit procedure gives us a model-independent measure of the spectral evolution of the prompt component, which can readily be converted to specific spectral model to compare with theory; and enables us to place constraints on the rise time and rate of the afterglow onset in the X-ray band, and to measure the Lorentz factor of the Gamma Ray Burst outflow. These details are crucial to understand the origin and location of the afterglow emission.

The optical counterpart to the hyperluminous X-ray source HLX1

Author: George Hau

ESO

Co-Authors: R. Soria (MSSL)

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Poster

Summary:

The existence of intermediate-mass black holes (IMBHs)-- black holes of masses between 1 thousand and 1 million solar masses -- has important implications for the formation and evolution of star clusters and supermassive black holes. The hyperluminous X-ray source HLX1 located in the S0 galaxy ESO 243-49 (Soria et al 2010, Farrell et al 2010) represents one of the strongest candidates for their existence. We have performed deep VLT/VIMOS UBVRI photometry of HLX1 and its host star cluster. I will present the latest analysis on the stellar populations of the host cluster, the constraints on the nature of HLX1, and examine the connection between HLX1 and the host galaxy.

Fluid jet model of blazars

Author: William Potter

University of Oxford

Co-Authors: G.Cotter (University of Oxford)

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Poster

Summary:

I present the findings of my work on an adiabatic fluid jet model for blazars. This includes a thorough treatment of inverse-compton scattering from synchrotron radiation from the same population of electrons and from CMB and accretion disc seed photons. The jet is modelled as an axisymmetric adiabatic fluid expanding with a constant opening angle. The model reproduces observed blazar properties including the flat radio spectrum, synchrotron and inverse-compton peaks and also flaring of the inverse-compton emission induced by flaring of the accretion disc.

Results from the Swift Supergiant Fast X-ray Transients Project

Author: Claudio Pagani

University of Leicester

Co-Authors: P. Romano (INAF-IASF Palermo), P.A. Evans (UL), K.L. Page (UL), on behalf of the Swift SFXT Project

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Poster

Summary:

Supergiant Fast X-ray Transients (SFXTs) are a class of High Mass X-ray Binaries, first discovered by the INTEGRAL satellite, characterized by their short outburst emission and the association with blue supergiant companions. The Swift satellite is uniquely and ideally suited to study SFXTs thanks to its sensitivity, the broadband coverage and its scheduling flexibility. We illustrate here the main results from the observing campaigns on SFXTs performed by Swift during the last four years. The monitoring allowed, for the first time, the study of the onset of an outburst, and the broadband modelling of the outburst emission; it showed that the outburst events are longer than previously measured by INTEGRAL and led to the discovery of X-ray emission during an intermediate state of low accretion outside of outburst. The Swift monitoring has given insights into the source of the observed emission and the mechanisms that trigger the system outbursts.

High-redshift quasar selection in VIKING

Author: Joseph Findlay

QMUL

Co-Authors:

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Poster

Summary:

Over the last ten years, optical surveys such as the Sloan Digital Sky Survey and the Canada-France High-redshift Quasar Survey have increased the number of known quasars at z ~ 6 to over 50. The key to the photometric selection of a strong quasar candidate is to isolate the characteristic absorption break blueward of the Lyman alpha transition brought about by intervening HI. At z > 6 Lyman-alpha begins to shift out of the Sloan z' band and into the near-IR. While progress towards higher redshifts is possible in a predominantly optical parameter space (e.g. PanStarrs) faint optical detections make it difficult to reject the numerous Galactic stars with scattered quasar like colours that out number high-z quasars by a factor ~ 10^4. To this end a number of other surveys have taken a different approach, employing the near-IR as their selection space, a tactic which has had recent encouraging success in e.g. UKIDSS. The ESO public VISTA Kilo-degree Infrared Galaxy survey (VIKING) is another near-IR based survey that is nearing its first public data release. VIKING's combination of depth and area is ideally suited for quasar searches at the highest redshifts. Here I will introduce the VIKING survey and the numerous motivations for discovering quasars beyond z ~ 6. I will then look at the detailed selection processes involved in isolating the strongest candidates for follow-up from the large number of false positives occupying the VIKING quasar selection space.

Observing with Swift

Author: Julian Osborne

University of Leicester

Co-Authors: Andrew Beardmore, Phil Evans, Christopher Mountford, Paul O'Brien, Claudio Pagani, Kim Page (University of Leicester)

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Poster

Summary:

Swift is a sensitive hard X-ray, X-ray, UV and visual band observatory with open access to both pre-planned and rapid-response target-of-opportunity proposals. TOOs of a few kiloseconds observing time can at a few hours to days notice, with the data delivered within hours. Larger proposals may be submitted to the annual Guest Investigator program (which this year will allow proposals of >100 targets or >100 ksec). Support for proposers is available from the UK Swift Science Data Centre (http://www.swift.ac.uk/). Astronomers are encouraged to make use of this valuable observing facility, which is easy to use, quick to respond, and for which support is available.

A Fermi-LAT Study of the Active Galaxy NGC 1275

Author: Kate L Dutson

University of Leicester

Co-Authors: R.J. White (University of Leicester) J.A. Hinton (University of Leicester) A.C. Edge (Durham University)

Session: EXP: Explosive transients, AGNs and black holes

Presentation type: Poster

Summary:

The active galaxy NGC 1275 has now been detected in High Energy and Very High Energy gamma-rays (using the Fermi-LAT and MAGIC telescopes respectively), raising questions about the mechanisms responsible for producing such energetic emission in the centre of the well-known Perseus cluster of galaxies. Could it be associated with the relativistic outflow from the central engine, which is believed to inflate bubbles tens of kiloparsecs into the Intracluster Medium, or do the gamma-rays originate from larger scale structures? The temporal variability of the Fermi source, and spectral evolution over the course of two recent flaring events was investigated, making it possible to probe the physical extent and particle composition of the emission region. Evidence was found for flux variability on timescales down to 14 days, suggestive of emission originating very close to the super-massive black hole, and spectral hardening during both flares, perhaps associated with the injection of accelerated particles prior to the detection of an increased flux of ~GeV photons. Given the wider implications of these results for the object class, studies of other cooling core clusters with Fermi-LAT are underway, and will be presented at the meeting.

Magnetic flux emergence: a precursor of solar dynamic events.

Author: Vasilis Archontis

University of St Andrews

Co-Authors:

Session: FLU: Flux emergence and eruptions

Presentation type: Talk

Summary:

We present numerical experiments and observations from recent solar missions that shed new light on the dynamical emergence of magnetic fields from the solar interior to the corona. We describe the response of the highly stratified solar atmosphere on flux emergence and, consequently, we attempt to introduce a comprehensive picture of the coupling between solar dynamic phenomena and the emergence of magnetic flux.

New Flux Emergence into an Existing Active Region

Author: Prof Alan Hood

University of St Andrews

Co-Authors:

Session: FLU: Flux emergence and eruptions

Presentation type: Talk

Summary:

In many cases, magnetic flux emerges beside or inside a previously emerged active region. The immediate interaction between the two flux systems can create many dynamic phenomena. Simulations of this process have been undertaken and show evidence of (i) strong current sheet formation, with plasmoid formation and ejection from the sheet, (ii) flux rope formation and a larger ejection of dense plasma and (iii) reconnection between the two flux systems and the creation of hot dense loops.

Flux emergence of the active region: the first 8 hours

Author: Stephane Regnier

University of Central Lancashire

Co-Authors:

Session: FLU: Flux emergence and eruptions

Presentation type: Talk

Summary:

In Feb. 2010, the Solar Dynamics Observatory (SDO) was launched. SDO is dedicated to the study of the Sun's magnetic activity and the associated coronal responses. Using the combination of observations provided by both the imager SDO/AIA (5 wavelengths at 45s cadence) and the magnetograph SDO/HMI (line-of-sight magnetograms at 45s cadence), we study the emergence of a peculiar active region from the photosphere to the million degree corona. Focusing on the first 8 hours of the emergence stage until the creation of a pore, we show that the active region emerges near the boundary of a supergranular cell and does not evidence any rotational motions contrary to models of emerging twisted flux tubes. The mass loading into the corona and the ubiquitous presence of flows are highlighted by the coronal observations from 50000K to 2 MK. We also evidence the thermal structure of the emerging active region (thermal shielding) as well as the interaction between the emerged magnetic field and the pre-existing coronal field through successive reconnection. We compare this evolution to numerical models of flux emergence.

Disentangling the Properties of Magnetic Bright Points

Author: Peter Keys

Queen

Co-Authors:

Session: FLU: Flux emergence and eruptions

Presentation type: Talk

Summary:

Magnetic bright points (MBPs) are believed to be the footpoints of magnetic flux tubes in the solar atmosphere, and can be seen as bright structures within the dark inter-granular lanes. They cover a sizeable portion of the solar disc and can act as a conduit for imparting kinetic energy into the upper solar atmosphere. Due to the small sizes of MBPs, only recently has it been possible to complete full studies of these small, dynamic features with advancements in adaptive optics and improvements in image reconstruction techniques. We use G-band images obtained with the Rapid Oscillations in the Solar Atmosphere (ROSA) instrument to identify 3185 MBPs and study their evolving velocity characteristics. The observational findings are compared with simulations of radiative magneto-convection.

Coronal outflows and radio noise storms in active regions

Author: Giulio Del Zanna

University of Cambridge

Co-Authors: G. Aulanier, K.L.Klein, T. Torok (LESIA, Observatoire de Paris)

Session: FLU: Flux emergence and eruptions

Presentation type: Talk

Summary:

We propose a unified interpretation for persistent coronal outflows and metric radio noise storms, two phenomena typically observed in association with quiescent solar active regions. Our interpretation is based on multi-wavelength observations supplemented by an analysis of the coronal magnetic field topology. We suggest that the continuous flux emergence in active regions maintains a steady reconnection between closed, high-density loops in the core and neighbouring open, low-density flux tubes. The reconnection drives the plasma upflows and sustains the radio noise storm in the closed loop areas, as well as weak type III emission along the open field lines. This interpretation has many important consequences,if confirmed.

Dynamics in the solar atmosphere due to emerging flux observed by Hinode and SDO

Author: David Shelton

MSSL/UCL

Co-Authors: Professor L.Harra Doctor L. Green

Session: FLU: Flux emergence and eruptions

Presentation type: Poster

Summary:

Magnetic flux emergence into the solar atmosphere can create violent events such as solar flares, jets and coronal mass ejections as the new flux interacts with the pre-existing field. For the past few years we have been at solar minimum meaning that major flux emergence events which form active regions , and the associated solar activity, has been at a minimum. We are now returning to a period of high activity on the Sun. We present data from the Solar Dynamics Observatory and the EIS instrument on Hinode on an active region present on the solar disk between the 20th October and 30th October 2010. New magnetic flux was observed to emerge into the pre-existing active region over a timesame of 4 days. We present our initial findings of our study into how energy is transferred from below to above the solar surface during this flux emergence event.

High resolution observations of a B-class flare

Author: David Jess

Queen

Co-Authors: P. H. Keys (QUB); R. Milligan (QUB); M. Mathioudakis (QUB)

Session: FLU: Flux emergence and eruptions

Presentation type: Poster

Summary:

On the 29 October 2010, NOAA AR 11117 erupted producing a B2 flare. This event was captured by both the Rapid Oscillations in the Solar Atmosphere (ROSA) and Interferometric BI-dimensional Spectrometer camera systems. Using a range of optical filters, incorporating blue-continuum, H-alpha, Fe I and Sodium D1 observations, we piece together the progression of this low-energy flare at the highest possible spatial, spectral and temporal resolutions.

Episodic Hard X-ray Bursts in Solar Flares

Author: Aidan O

Trinity College, Dublin

Co-Authors: P.T.Gallagher

Session: FLU: Flux emergence and eruptions

Presentation type: Poster

Summary:

During solar flares, hard X-rays (HXR) are emitted by accelerated electrons interacting with the dense underlying chromosphere. HXR spectra observed during these peaks can be used to calculate the properties of the flaring plasma, such as the density distributions at the time of the peak (e.g., Aschwanden et al. 2002). However, the impulsive nature of HXR bursts and the difficulties associated with HXR imaging-spectroscopy makes this a challenging task. Here, a flare that exhibited multiple separated HXR peaks is described, and used to determine the evolution of the flaring plasma with time. Our results provide new information on the structure of plasma in flaring loops and on the fundamental physics of chromospheric evaporation.

Granular-scale magnetic flux emergence within an emerging active region

Author: Santiago Vargas Dominguez

Mullard Space Science Laboratory (UCL)

Co-Authors: L. van Driel-Geztelyi (MSSL/UCL, Observatoire de Paris, Konkoly Observatory of Hungarian Academy of Sciences)

Session: FLU: Flux emergence and eruptions

Presentation type: Poster

Summary:

In this work we analyze data from the Hinode spacecraft targeting an emerging magnetic flux region.We focus on small-scale events identified by distinctive dark features in CaII H chromospheric filtergrams. Energy release at low chromospheric heights is detected to be boosted by the disappearance of the dark features after they reached their maximum size. The observed phenomena are explained as evidencing elementary flux emergence into the solar atmosphere. We are thus detecting granular-scale arch filament systems, that emerge and interact with pre-existing fields.

Euclid: measuring dark energy

Author: Mark Cropper

Mullard Space Science Laboratory, UCL

Co-Authors: The Euclid Consortium

Session: FUT: Future windows on the Universe

Presentation type: Talk

Summary:

Euclid is an ESA candidate medium mission, which, if selected in the final competitive round in October, will launch in 2018. It will image the entire extraGalactic sky with 0.2 arcsec spatial resolution in the visible, and only slightly worse in the infrared, down to AB>24, and will also provide spectroscopy in the infrared continuum to HAB>19.5. This will produce a huge legacy dataset, with widespread application. Euclidâ€™s core science goals are cosmological, with multiple, independent measures on cosmological parameters in order to explore the dark matter and dark energy components of the Universe, and to test alternative scenarios. UK groups have strong roles in this high profile mission. This presentation will briefly describe the mission, and the expected science return.

Future X-ray missions: the next 15 years

Author: Mike Watson

University of Leicester

Co-Authors:

Session: FUT: Future windows on the Universe

Presentation type: Talk

Summary:

The next five years will see the launch of several X-ray missions - AstroSat, eRosita, NuStar, Astro-H & GEMS - which bring new or enhanced capabilities, including true X-ray imaging at high energies, high spectral resolution imaging and X-ray polarimetry, all of which will enable new aspects of the high energy Universe to be explored. Beyond that the situation is less clear, but ESA's future programme may include LOFT, a large-area X-ray timing mission. In addition a re-scoped version of IXO, and observatory-class X-ray project, remains a contender for an ESA L-class mission in 2022. I will briefly review the likely science impact of the near-future, approved missions and summarise the prospects for IXO.

The cost window: can we do observatory-class science with small space missions?

Author: Martin Barstow

University of Leicester

Co-Authors:

Session: FUT: Future windows on the Universe

Presentation type: Talk

Summary:

Even before the current financial crisis, it was becoming difficult to sustain the level of expenditure required to provide the range of space astronomy missions that the research community would like to see. The multi-billion pound/dollar observatories that we might hope would follow the successes of Chandra, XMM-Newton, HST and JWST continue to slip into the future, while the medium size ESA and NASA missions provide a small number of opportunities over the next decade. Much exciting and important science, by default, will not be done. If satellite mission costs could be reduced significantly, by a factor of 5-10, we would open up a new parameter space of opportunity that is not currently offered by any agency. Recently, significant improvements in instrument technology coupled with simplification of optical systems has led to the prospect of the development of some low-cost opportunities. These concepts will be outlined and the prospects of developing them into real flight opportunities in the near future discussed.

The Gaia Revolution: the legacy of ESA

Author: George Seabroke

Mullard Space Science Laboratory, University College London

Co-Authors: M. Cropper (MSSL, UCL); G. Gilmore (IoA, Cambridge); on behalf of the UK Gaia Consortium

Session: FUT: Future windows on the Universe

Presentation type: Talk

Summary:

The Gaia satellite is a high-precision astrometry, photometry and spectroscopic ESA cornerstone mission, scheduled for launch in 2013. This talk will explore the science motivations and technical and practical challenges of Gaia, highlighting the UK's and MSSL's involvement. The final Gaia catalogue containing the positions, distances, space motions and many physical characteristics of some one billion stars in our Galaxy and beyond will be released in the 2020s. This talk will present the expected accuracy of the final Gaia catalogue and show how it will revolutionise most of astrophysics, highlighting the synergies with other key future facilities expected to be available to astronomers in the 2020s. However, one does not have to wait until the 2020s for Gaia data. The UK is responsible for the first Gaia data to go public from 2013-2014 onwards: transient phenomena (e.g. type Ia supernovae) will trigger Gaia Science Alerts that will be released within about one day of observation. Ambitions include a new improved Hipparcos proper motion catalogue to be released in 2014 by combining the first 6 months of Gaia astrometric data with Hipparcos data. The legacy value will increase during the mission through two intermediate Gaia catalogues with ever increasing data accuracy.

The Cherenkov Telescope Array

Author: Garret Cotter

University of Oxford

Co-Authors:

Session: FUT: Future windows on the Universe

Presentation type: Talk

Summary:

The Cherenkov Telescope Array (CTA) is a global project to build the next-generation observatory for ground-based very-high-energy gamma-ray astronomy. The CTA consortium comprises scientists working in 26 countries and the project is a highlight of roadmaps such as ASTRONET, ASPERA and the US Decadal Review. CTA will consist of two arrays of imaging air Cherenkov telescopes, one in the northern and one in the southern hemisphere. A range of telescope sizes from ~20-m to ~4-m will offer unprecedented sensitivity and angular resolution from 50 GeV to >100 TeV. CTA will allow discovery and advance in the fields of galactic and extragalactic relativistic jet physics, pulsars, supernova remnants, gamma-ray bursts, star formation and particle acceleration, as well as many aspects of fundamental particle physics. I will describe the current status of the project and consider science prospects with particular emphasis on astrophysics topics and synergies with future facilities at other wavelengths.

Status of the European Extremely Large Telescope

Author: Colin Cunningham

UK Astronomy Technology Centre, Royal Observatory Edinburgh

Co-Authors:

Session: FUT: Future windows on the Universe

Presentation type: Talk

Summary:

We in a critical year for the E-ELT, with a new member state for ESO putting the project on a much sounder financial footing. We expect a proposal to go to ESO Council this year, with construction starting soon after. I will give an update on progress on the telescope, instrument and adaptive optics systems design since the technical review in September 2010. Emphasis will be placed on UK science, instrumentation and industrial interests.

CANARY: On-sky results from the first tomographic MOAO demonstrator

Author: Tim Morris

University of Durham

Co-Authors:

Session: FUT: Future windows on the Universe

Presentation type: Talk

Summary:

Achieving adaptive optics correction over fields of view wider than 10-20" is a large technical challenge, but is required to fully optimise science return over the large 5â€™-10â€™ diameter field afforded by the E-ELT. Multiple Object Adaptive Optics (MOAO) is the only technique available for providing high resolution imaging over such a wide field. MOAO systems will provide adaptive optics correction along multiple lines of sight and are well suited to observations of sparsely populated target fields, such as large surveys of high-z galaxies. The CANARY instrument is an MOAO demonstrator that aims to emulate a single channel of the proposed EAGLE MOAO instrument for the E-ELT, principally to confirm MOAO performance, but also to demonstrate the techniques required to calibrate such a system are well understood. CANARY was deployed on the 4.2m William Herschel Telescope in September 2010 and here we present initial results from the on-sky testing of the Phase A Natural Guide Star (NGS) based system. Later phases of CANARY will introduce Laser Guide Star (LGS) based tomography using a 30W laser fired from behind the WHT secondary mirror and woofer-tweeter deformable mirror control.

High contrast integral field spectroscopy for exo-planet detection.

Author: Fraser Clarke

University of Oxford

Co-Authors: G.Salter (University of Oxford, University of New South Wales), N.Thatte (University of Oxford), M.Tecza (University of Oxford)

Session: FUT: Future windows on the Universe

Presentation type: Talk

Summary:

Direct detection of exo-solar planets uses extreme adaptive optics and high performance coronagraphs to achieve contrasts exceeding 1 part in 10 million at angular separations of only few tenths of an arc second from the parent star. The next generation planet finder - the EPICS instrument at the E-ELT, aims to achieve contrasts of 1 part in a billion (10^9) so as to enable direct detection and spectroscopy of earth-like planets and super-earths. The use of differential observing techniques is a must to beat the speckle noise limit, and integral field spectrographs, coupled with spectral deconvolution, provide a promising way of achieving the required contrast. We have carried out laboratory measurements of speckle rejection achieved using image slicer based integral field spectrographs, and show that contrasts of several hundred, and up to 1000 can be achieved from the integral field spectrograph alone (the present generation of planet finders assumes only a contrast of 10-20 from the back-end differential measurement instrument). We present our experimental results, and discuss limitations to achievable contrast

New spectral diagnostics for studies of extragalactic stellar populations

Author: Chris Evans

UKATC

Co-Authors: B. Davies (Cambridge), R.-P. Kudritzki (Hawaii/MPIA)

Session: FUT: Future windows on the Universe

Presentation type: Talk

Summary:

Plans for the next generation of optical-infrared telescopes, the Extremely Large Telescopes (ELTs) are well advanced. With primary apertures in excess of 20m, combined with enhanced image quality from adaptive optics, they will revolutionise our ground-based capabilities. I will present new simulations of J-band spectroscopy of extragalactic red giants and supergiants, undertaken as part of the EAGLE instrument study, but which are also very promising for upcoming instruments such as VLT-KMOS. In terms of of recovering stellar metallicities for a given target, this method is more sensitive than contemporary methods which employ the calcium triplet, offering the potential of extragalactic stellar abundances out to tens of Mpc.

Science with VLTs and smaller telescopes in the ELT era

Author: Phil Charles

SAAO

Co-Authors:

Session: FUT: Future windows on the Universe

Presentation type: Talk

Summary:

It is remarkable that there are now almost as many VLTs as there are 4m-class telescopes, and this has driven the demand for the even larger apertures of ELTs. While ELTs are still a decade away, it is interesting to consider the role that VLTs will play in that era. A glimpse of likely directions is afforded by the role that smaller telescopes (<2m) are playing at the present time. Indeed, there has been a huge increase in the number of dedicated small telescopes in recent years. I will illustrate these points by referencing the range of new (mostly robotic) facilities at SAAO, as well as highlighting the scientific advantages of a fully queue-scheduled 10m-class telescope like SALT, and how to exploit them once ELTs and JWST are operational.

WEAVE - The WHT Enhanced Area Velocity Explorer

Author: Gavin Dalton

RAL Space and University of Oxford

Co-Authors:

Session: FUT: Future windows on the Universe

Presentation type: Talk

Summary:

I will present the details of a new prime focus facility for the William Herschel Telescope targetting Northern Hemisphere follow-up of ground- and space-based survey facilities such as GAIA and LOFAR. WEAVE will provide spectroscopy of 1000 simultaneous targets at R=5000 with full optical wavelength coverage, R=20000 spectroscopy with a reduced wavelength range, and single and multiple IFU modes for the follow-up of extended sources.

Optical interferometry comes of age. What is next?

Author: Ettore Pedretti

School of Physics and Astronomy, University of St Andrews

Co-Authors: C.A. Haniff(Cavendish Laboratory, University of Cambridge); F. Delplancke (European Organisation for Astronomical Research in the Southern Hemisphere); D.F. Buscher (Cavendish Laboratory, University of Cambridge); J.S. Young (Cavendish Laboratory, University of Cambridge)

Session: FUT: Future windows on the Universe

Presentation type: Talk

Summary:

The exploitation, by non-expert users, of optical/infrared synthesis arrays, such as the VLTI, CHARA and Keck interferometers, has demonstrated that their scientific productivity is mirroring that of the first generation of radio interferometers. Applications in stellar imaging, asteroseismology, extra-solar planet searching, star and disk formation, and AGN astrophysics have all been reported. Furthermore, the science impact of such arrays is set to increase as further new interferometric instruments with enhanced sensitivity and imaging fidelity are rolled out. In this talk we outline the UK's potential scientific opportunities in the field in the 2-10 year time frame and review the technical developments and new facilities that are expected to come on line in this period.

ALMA: Status and Early Science Opportunities

Author: John Richer

Cavendish/Kavli, Cambridge

Co-Authors:

Session: FUT: Future windows on the Universe

Presentation type: Talk

Summary:

ALMA is finally producing its first test images, and the first call for proposals is imminent. I will describe the status of ALMA construction, show first imaging and spectroscopic results, and describe the opportunities for the first open science projects.

The SPICA mission

Author: Matt Griffin

Cardiff University

Co-Authors:

Session: FUT: Future windows on the Universe

Presentation type: Talk

Summary:

The Japanese Space Infrared telescope for Cosmology and Astrophysics (SPICA) will be the next major infrared space astronomy mission. It will carry a 3.2-m telescope cooled to ~ 6 K by mechanical coolers, and a suite of instruments covering the 5 - 200 micron range. SPICA's large, cold aperture will provide a huge increase in sensitivity over current far infrared facilities. SPICA will have a significant European involvement through provision of the telescope and the SAFARI FIR imager and spectrometer. I will outline the current design and status of SPICA and summarise its scientific capabilities.

Centimetre-wave radio astronomy in the run up to the SKA

Author: Michael Jones

University of Oxford

Co-Authors:

Session: FUT: Future windows on the Universe

Presentation type: Talk

Summary:

In the decade or so before the Square Kilometre Array comes fully on line, there are still many exciting opportunities for ground-based centimetre-wave astronomy. The C-Band All-Sky-Survey (C-BASS), currently under way, is the first all-sky radio (5 GHz) survey attempted from the ground for many years, and uniquely will used matched telescopes and receivers in both hemispheres to obtain uniformity and accuracy of coverage. It is intended to complement the space-based all-sky maps from WMAP and Planck, and will lead to more accurate CMB intensity and polarization data, as well as providing the most detailed maps of the Galactic synchrotron emission and magnetic field structure. C-BASS South is based at site of MeerKAT in South Africa, which will provide unprecedented survey capability across a wide range of radio frequencies, and is a pathfinder to the next scale of large dish arrays. Currently emerging technologies such as low-cost, mass-producible cryogenic radio receivers, large single-piece reflectors, high-bandwidth backend electronics, and novel correlation and imaging schemes will lead to instruments with first hundreds and then thousands of elements, with vastly improved capabilities for surveys and deep imaging.

European and Global Arrays in the SKA Era

Author: Simon Garrington

JBCA, University of Manchester

Co-Authors:

Session: FUT: Future windows on the Universe

Presentation type: Talk

Summary:

As the Square Kilometre Array is being designed, existing arrays of radio telescopes in the UK, in Europe and across the world continue to play a vital role scientifically and technically. As SKA pathfinders they are pushing a range of technical developments from receivers, wide-band data links, correlators and data analysis. And as the SKA comes in to operation these arrays can continue to complement the SKA providing high-frequency and long-baseline imaging as well as northern-hemisphere coverage and a global extension of longest SKA baselines. This talk will include updates and scientific potential of e-MERLIN, the European VLBI Network and global VLBI networks.

Transformational science with the SKA

Author: Paul Alexander

University of Cambridge

Co-Authors: The UK SKA team

Session: FUT: Future windows on the Universe

Presentation type: Talk

Summary:

I will discuss the science that will be delivered by the SKA and the current phasing of the project. Phase 1 of the SKA (SKA1) is scheduled to start construction in 2016 and will itself provide a major scientific advance on current radio astronomical instruments.

Author: Lisa Harvey-Smith

CSIRO Astronomy & Space Science

Co-Authors:

Session: FUT: Future windows on the Universe

Presentation type: Poster

Summary:

The Australian SKA Pathfinder is an aperture synthesis radio telescope currently under construction at the candidate site for the Square Kilometre Array (SKA) in Western Australia. In this talk I will describe some of the many unique features of ASKAP, including the telescope's focal plane arrays (radio cameras), the novel 3-axis dish steering system and the pristine radio-quiet environment. I will discuss some of the technical challenges these new technologies present and how they are overcome. As the construction of ASKAP is well underway, the latest pictures of recent progress from the site will be shown. Finally, the ASKAP science case will be discussed, in particular the potential for new discoveries in wide-field science and in the largely unexplored time domain.

Author: Chris Benn

Isaac Newton Group, La Palma

Co-Authors: Marc Balcells (Isaac Newton Group)

Session: FUT: Future windows on the Universe

Presentation type: Poster

Summary:

We review recent and possible future changes to the suite of northern-hemisphere optical telescopes accessible to UK astronomers, and consider the likely impact on UK astronomy. In particular, we review the implications for ground-based optical follow-up of space and radio surveys already in the pipeline, for studies of rare objects and events, for instrument development, and for the training of young astronomers.

The challenges of high precision spectroscopy

Author: Ulrike Lemke

Durham University

Co-Authors:

Session: FUT: Future windows on the Universe

Presentation type: Poster

Summary:

As telescope apertures increase in size and more sophisticated spectroscopic techniques become available, ever-higher signal-to-noise ratios and spectral resolutions come into reach. This progress will permit fundamental advances in a range of areas. For example, the magnetic field distribution of stellar atmospheres can be analysed with unprecedented precision. Furthermore, using radial velocity methods it will be possible to detect Earth-like planets orbiting host stars similar to the Sun. The optical fibre is a key technology in these developments. However, there are complications to consider when utilising fibres. Phenomena such as incomplete scrambling and modal noise produce temporal instabilities in intensity and central wavelength position of the spectral lines, ultimately limiting the spectrograph performance. I will briefly introduce these phenomena and give an overview of corrective techniques. As far as possible I will furnish estimates that will quantify these effects on astronomical measurements.

The Extragalactic Potential of SPICA and SAFARI

Author: David Clements

Imperial College London

Co-Authors: The SPICA-SAFARI Consortium

Session: FUT: Future windows on the Universe

Presentation type: Poster

Summary:

SPICA is the next generation space far-infrared space telescope and will follow on from the great success of Herschel. It will be a Japanese-led mission with ESA participation and a European instrument. SPICA will have a 3m class telescope with mechanically cooled instruments and telescope primary. This will allow a greater mission lifetime and, with the primary at ~10 times lower temperature than that of Herschel, much greater sensitivity. Essentially for anything that Herschel can detect in the continuum, SPICA-SAFARI will be able to obtain a spectrum. In this presentation we discuss the huge potential for extragalactic astronomy of SPICA and the European SAFARI far-IR imaging-spectrometer instrument.

LOFT (Large Observatory for X-ray Timing)

Author: Awat Rahimi

UCL - MSSL

Co-Authors: S. Zane, R.P. MIgnani, D. Walton, A. Smith, R. Cole, B. Winter, P. Guttridge, D. Kataria, P. Smith, on behalf of the LOFT Science Team

Session: FUT: Future windows on the Universe

Presentation type: Poster

Summary:

LOFT (Large Observatory for X-ray Timing) is one of the four M3 missions that have been selected by ESA for an Assessment Phase with launch in 2020-2022. LOFT is specifically designed to study the very rapid X-ray flux and spectral variability that directly probe the motion of matter down to distances very close to black holes and neutron stars. The 10 m2 Large Area Detector (LAD), with its temporal (a few nsec) and spectral resolution (<260 eV around 6 keV), allows to exploit the relevant astrophysical diagnostics and holds the potential to revolutionise the study of collapsed objects in our galaxy and of the brightest supermassive black holes in active galactic nuclei. We illustrate the scientific goals of the mission and the major role played by the Mullard Space Science Laboratory and UK partner institutes in the LOFT Science Team.

First e-Merlin Test Images of Faint AGN in GOODS-N

Author: Dr Tom Muxlow

Jodrell Bank Centre for Astrophysics

Co-Authors: Dr Robert Beswick (Jodrell Bank Centre for Astrophysics)

Session: FUT: Future windows on the Universe

Presentation type: Poster

Summary:

As a prelude to the e-MERGE Legacy project, e-Merlin test observations have been made of the central region over a frequency range of 6.0-6.5 GHz utilizing the new wide-bandwidth optical fibre connections and WIDAR correlator. This illustrates the ability of e-Merlin to detect and image weak AGN cores in distant star-forming galaxies.

Black Holes and Starbursts in the Cosmic Web

Author: Ryan C. Hickox

Durham University

Co-Authors:

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

It is increasingly clear that the evolution of galaxies is linked to the growth of their parent dark matter halos as well as their central supermassive black holes. I will present recent studies that explore these connections through the spatial clustering (and thus halo mass) and host galaxy characteristics of active galactic nuclei and starbursts, with a focus on obscured quasars and submillimeter galaxies (SMGs). Our results support a picture in which SMGs and quasars share a common evolutionary path, possibly fuelled by major mergers or violent instabilities. These studies also show that black hole hole accretion declines along with star formation in massive halos, while more efficiently producing mechanical outflows as required by some galaxy evolution models. To close, I will briefly discuss opportunities with the next generation of infrared and X-ray observatories.

The mass and size evolution of the most massive galaxies

Author: John Stott

Durham University

Co-Authors:

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

Brightest cluster galaxies (BCGs) are the most massive stellar systems in the Universe, residing at the centres of the largest potential wells and are thus ideal objects for studying hierarchical assembly. I present new results from our Subaru MOIRCS and VLT HAWKI imaging surveys of 20 of the most distant X-ray selected clusters, using near-infrared light as a proxy for stellar mass, to investigate BCG merger activity since redshift 1.5. In a parallel study we exploit deep HST imaging data for a subset of this sample to look for evidence of an evolution in the scale size and light profile shape of BCGs in order to constrain their evolution further.

Does environment matter at z>2?

Author: Nina Hatch

University of Nottingham

Co-Authors:

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

The effects of environment on galaxy evolution are most obvious when comparing galaxies in highly contrasting environments. To investigate the influence of environment in the early Universe we present a study which compares z~2 field galaxies to those in proto-clusters, some of the densest environments at z>2. We use these early progenitors of galaxy clusters to understand how environment affects galaxies during their formative epoch. We select clean samples of z~2 proto-cluster and field H-alpha emitters and compare their properties, including stellar mass, star formation rate, colour and specific star formation rate. I will show that the proto-cluster galaxies are rapidly forming stars in a similar manner to field galaxies. However, the proto-cluster galaxies are already twice as massive, and have lower specific star formation rates than their field counterparts. Thus the proto-cluster galaxies are further evolved than the field galaxies. This study implies that dense environments promotes galaxy growth in the early Universe, and that cluster galaxies differed from field galaxies even before the clusters virialized.

Cosmic evolution of star formation and the gas content of galaxies

Author: Claudia Lagos

Institute of Computational Cosmology, Durham University

Co-Authors: Baugh C (ICC), Lacey C. (ICC), Bower R. (ICC), Benson A. (CALTECH), Power C. (Swinburne), Kim H.-S. (Melbourne)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

We investigate the star formation and the gas content of galaxies by splitting the interstellar medium into its atomic and molecular hydrogen components, using the galaxy formation model GALFORM in the CDM framework. We calculate the ratio of molecular to atomic hydrogen, H2/HI, in each galaxy self-consistently and calculate the star formation rate based on the H2 content. We are able to predict the HI mass function, the CO(1-0) luminosity function, the correlations between H2/HI and stellar and cold gas mass, and the far-infrared-CO luminosity relation, which are in good agreement with local and high redshift observations. We also predict the HI and H2 mass functions up to z=8 and find that these are characterised by radically different evolution: for HI the number density of massive objects decreases slowly with increasing redshift, while for H2 the maximum number density of massive objects is reached at z~2. We also find that the ratio H2/HI is strongly dependent on stellar and cold gas mass, and also on redshift. The predicted cosmic density evolution of HI agrees with the observed evolution inferred from damped-Lya systems, and is always dominated by the HI content of low and intermediate mass halos. We predict that the star formation rate vs. stellar mass plane should have two sequences of "active" and "passive" galaxies, in agreement with local observations, and show that the evolution of this plane offers a means to constrain the SF law.

Early Star Forming Galaxies and Cosmic Reionization

Author: Dan Stark

University of Cambridge

Co-Authors:

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

The first billion years of cosmic history is one of the final 'missing chapters' in the detailed story of galaxy evolution. Deep imaging surveys with HST and Spitzer have recently provided the first census of star forming systems at 5

Galaxy evolution at redshifts 6 < z < 9

Author: Ross McLure

Institute for Astronomy, Edinburgh University

Co-Authors:

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

The search for ultra high-redshift galaxies is motivated by the desire to constrain the earliest phases of galaxy evolution, and to uncover the nature of the sources responsible for cosmic reionization. In recent years this subject has been revolutionised by a combination of wide-area, multi-wavelength survey campaigns and ultra-deep, pencil-beam HST imaging. The main body of the talk will summarise recent work undertaken at the Institute for Astronomy in Edinburgh to study the luminosity function, stellar masses and star-formation rates of the 6 < z < 9 galaxy population, using a combination of the UKIDSS Ultra-Deep Survey and high-resolution HST imaging. In addition, I will discuss recent spectroscopic results at z>7 and outline the opportunities offered by a major new near-IR imaging programme on HST (CANDELS). With a total allocation of 902 orbits, CANDELS is the largest ever HST programme, and promises to deliver the first statistical sample of massive galaxies at z>7.

The galaxies that reionized the Universe

Author: tom theuns

durham university

Co-Authors:

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

The Durham GALFORM semi-analytical galaxy formation model has been shown to reproduce the observed rest-frame 1500-Ã… luminosity function of galaxies well over the whole redshift range z = 5â€“10. We show that in this model, this galaxy population also emits enough ionizing photons to reionize the Universe by redshift z = 10, assuming a modest escape fraction of 20 per cent. The bulk of the ionizing photons is produced in faint galaxies during starbursts triggered by galaxy mergers. The bursts introduce a dispersion up to âˆ¼5 dex in galaxy-ionizing luminosity at a given halo mass. Almost 90 per cent of the ionizing photons emitted at z = 10 are from galaxies below the current observational detection limit at that redshift. Photoionization suppression of star formation in these galaxies is unlikely to affect this conclusion significantly, because the gas that fuels the starbursts has already cooled out of their host haloes. The galaxies that dominate the ionizing emissivity at z = 10 are faint, with M1500magnitude of âˆ’16, have low star formation rates of 0.06 solar masses per year, and reside in haloes of mass around 10^9 solar masses.

The Large and Small Sagittarius Streams

Author: Vasily Belokurov

Institute of Astronomy

Co-Authors:

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

Using photometry from the Sloan Digital Sky Survey Data Release 8 in both Northern and Southern Galactic hemispheres, we show that some 10 degrees away from the Sagittarius tidal track, another fainter and metal-poorer stream is clearly visible. We provide strong evidence that the two streams follow very similar distance gradients but have distinct morphological properties and stellar populations. Gigantic metal-poor globular cluster NGC 2419 lies well within the debris of this faint stream not far from its predicted apo-centre.

Mismatch and Misalignment: Dark Haloes, Discs and Satellites

Author: Alis Deason

Cambridge (Institute of Astronomy)

Co-Authors: I.G. McCarthy (Cambridge); N.W. Evans (Cambridge); V. Belokurov (Cambridge); C.S. Frenk (Durham)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

It has been known for some time that the eleven classical satellites of the Milky Way define a highly inclined plane relative to the disc of the Galaxy. However, it is not obvious if this peculiar spatial distribution can be explained within the context of our standard CDM theory of structure formation. I use state-of-the-art hydrodynamic cosmological simulations to study the phase-space distributions of satellites belonging to disc galaxies. The alignment (in both position and velocity space) of the satellite galaxies relative to the disc is yet to be studied as previous work has made use of cold dark matter simulations. I find that misalignments between the galaxy and dark matter halo can have important consequences for the alignment of the satellites with the disc. I discuss the implications of this result to the Milky Way galaxy and to studies of external galaxies.

Surveying the M31 system

Author: Mike Irwin

Institute of Astronomy

Co-Authors:

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

Wide field imaging and spectroscopic surveys of the M31 system have revealed a complex web of substructure surrounding the classical visible galaxy, including: giant stellar streams; extended disk-like rotating components; unusual classes of stellar clusters and many new satellite galaxies. Even M33, long thought to be an undisturbed disk-dominated system, shows tantalising evidence of recent tidal interactions with M31. In this talk I will review some of the recent work on surveys in these systems and in particular discuss the latest results obtained from ground-based and space-based imaging and spectroscopic data.

The Halo Globular Cluster System of M31 as Revealed by PAndAS

Author: Avon Huxor

University of Bristol

Co-Authors: A.M.N. Ferguson (IfA, Edinburgh); N.R.Tanvir (Leicester); M.J.Irwin (IoA, Cambridge); A. McConnachie (Herzberg Institute, Canada); A.D.Mackey (ANU, Australia); R.A.Ibata (Strasbourg); T.Bridges (Queen's University, Canada); S.C. Chapman (IoA, Cambridge); G.F.Lewis (Sydney, Australia)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

Globular clusters (GCs) are excellent probes of galaxy formation and evolution. They are formed in the major star-bursts that accompany galaxy formation and gas-rich major mergers. The GCs of satellite galaxies also contribute to the GC system of a host after satellite accretion. I will present initial results from the recently completed CFHT/Megacam PAndAS survey of M31. We have identified many new GCs, which are present up to the edge of the survey (~ 120 kpc from M31), including additional 'extended clusters'. I will discuss how the properties of the halo GCs (individual and ensemble) provide strong support for a scenario in which a significant fraction of the outer halo GC population of M31 have been accreted.

Galaxy evolution within the Local Group - A spectroscopic survey of Andromeda

Author: Michelle Collins

Institute of Astronomy, Cambridge

Co-Authors: S. C. Chapman (Institute of Astronomy) R. M. Rich (UCLA) Mike Irwin (Institute of Astronomy) Rodrigo Ibata (Observatoire de Strasbourg) Alan McConnachie (NRC-Herzberg) Annette Ferguson (Institute for Astronomy)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

Over the past few years, a number of large scale photometric and spectroscopic surveys of the Andromeda galaxy have been embarked upon with the aim of understanding the processes that drive the formation and evolution of large spiral galaxies. In this contribution I will present new results from the spectroscopic side of the Pan-Andromeda Archaeological Survey (PAndAS), including the detection of a thick stellar disc in Andromeda that is chemically and kinematically distinct from the thin disc and halo. I will also discuss a survey of its satellite system, focusing on the the unexpected finding of subhalos in Andromeda that are kinematically colder than their Milky Way counterparts. When comparing these findings to what is observed in the Milky Way, significant differences in the structure and substructure of these two Local Group spirals are observed. This suggests that, while these galaxies have evolved within the same region of space, their evolutionary paths have been quite different from one another. I will discuss the implications of this for our understanding of spiral galaxy evolution.

Results from the ATLAS-3D survey of early-type galaxies

Author: Roger Davies

University of Oxford

Co-Authors: Katherine Alatal, (UC Berkeley) Leo Blitz (UC Berkeley) Maxime Bois (ESO & IAP Paris) Frederic Bournaud (AIM Saclay) Martin Bureau (Oxford Astrophysics) Michele Cappellari(Oxford Astrophysics) Timothy A. Davis (Oxford Astrophysics) P. T. de Zeeuw (ESO) Pierre-Alain Duc (AIM Saclay) Eric Emsellem (ESO) Jesus Falcon-Barroso (IAC) Sadegh Khochfar (MPE Munich) Davor Krajnovic (ESO) Harald Kuntschner (ESO) Pierre-Yves Lablanche (ESO & CRAL, Lyon) Raffaella Morganti (ASTRON & Groningen) Richard M. McDermid (Gemini) Thorsten Naab (MPA, Munich) Tom Oosterloo (ASTRON & Groningen) Marc Sarzi (U Herts) Nicholas Scott (Oxford Astrophysics) Paolo Serra (ASTRON, Dwingeloo) Anne-Marie Weijmans (Dunlap Institute, Toronto) Lisa M. Young (New Mexico Institute of Mining and Technology, Socorro)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

The SAURON survey of 72 local early type galaxies (ETGs) reveals an unexpected dichotomy of properties that depend on their specific angular momentum. Intrinsic shape, the nature of decoupled cores, age, M/L and ionised gas properties are all found to be significantly different for the ETGs with low specific angular momentum. I will present the SAURON results and report first results from the ATLAS-3D volume limited survey of 260 ETGs which give us a representative view of the local Universe and lead to a re-evaluation of the handle' of Hubble's tuning fork diagram.

Red but not dead! The Atlas3D view of the molecular ISM in early-type galaxies

Author: Timothy A. Davis

University of Oxford

Co-Authors: K.Alatalo (Berkeley); M.Bureau (Oxford); L.Blitz (Berkeley); L.M.Young (NMT) and the Atlas3D team

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

Over the past few years, early-type galaxies (ETGs) have shed their â€œred and deadâ€ moniker, thanks to the discovery that many host low-level residual star formation. As part of the Atlas3D project we are conducting a complete, volume limited survey of the stellar properties and ISM of 260 local ETGs. With this data we are attempting to understand the origin of the ISM, and study its distribution, kinematics and star formation properties. We detect molecular gas in â‰ˆ22% of ETGs in the local volume, and this detection rate is independent of galaxy luminosity and environment, but does depend on the galaxy kinematics. This molecular gas is usually distributed in relaxed central discs, polar structures and rings. The origin of the ISM does depend strongly on environment, with misaligned gas (indicative of externally acquired material) being common in the field but almost completely absent in the Virgo cluster. I will discuss these results and touch on implications for the formation and evolution of red sequence galaxies. I will also present the first molecular gas Tully-Fisher relation for ETGs, and show that molecules may be the kinematic tracer of choice for probing the M/L evolution of galaxies over cosmic-time.

Digging up the Dirt on Galaxies with Herschel

Author: Loretta Dunne

University of Nottingham

Co-Authors:

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

Hershel is the largest space telescope, operating in a largely unchartered region of the electromagnetic spectrum between 70-500 microns. It was launched in 2009 and will have a lifetime of approximately 3.5 years. Since it began operations, Herschel has shed new light on the hidden aspects of galaxy formation and evolution by providing information on the darkest, dustiest and coldest parts of the interstellar medium of galaxies. This talk will briefly highlight some of the key findings from Herschel studies of galaxies from several major programmes ranging from detailed studies of nearby galaxies to wide and deep surveys of the Universe.

Rapid evolution of dust in galaxies

Author: Haley Gomez

Cardiff University

Co-Authors: L Dunne (Nottingham University), E da Cunha (MPIA Heidelberg), K Rowlands (Nottingham University), D.J.B Smith (Nottingham University), S Charlot (IAP Paris), S Dye (Cardiff University), S Eales (Cardiff University), S J Maddox (Nottingham University) and the Herschel-ATLAS consortium

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

The Herschel Astrophysical Terahertz Large Area Survey (ATLAS) is the largest Open Time Key Project on the Herschel Space Observatory and will eventually cover 550 square degrees of the sky. We used data from the H-ATLAS science demonstration phase to present an unbiased measurement of the evolution of the dust mass function of galaxies over the past five billion years of cosmic history. We find that the ATLAS galaxies are dominated by cold dust at 15-25 K. The dust masses for the most massive galaxies are about five times larger at redshifts of 0.4-0.5 compared to those in the local Universe. We find the dust-to-stellar mass ratios are three-four times larger in the past. The increase in the dust content of massive galaxies at high redshift is difficult to explain using standard dust evolution models and requires a rapid gas consumption timescale together with either a more top-heavy IMF or a non-stellar source of dust e.g. grain growth in the interstellar medium. The latter model implies that less than 10% of dust in galaxies is provided by stars.

Dusty early-type galaxies in Herschel ATLAS

Author: Kate Rowlands

University of Nottingham

Co-Authors: L. Dunne, S. Maddox, N. Bourne (University of Nottingham), H. Gomez (Cardiff University), S. Kaviraj (Imperial College London), S.P.Bamford (University of Nottingham), S. Brough (Anglo Australian Observatory), S. Charlot (Institut d'Astrophysique de Paris), E. da Cunha (University of Crete, MPIA Heidelberg), S.A. Eales (Cardiff University), M. Gunawardhana (University of Sydney), A. Hopkins (Anglo Australian Observatory), A.E. Sansom (University of Central Lancashire), R. Sharp (Anglo Australian Observatory), D.J.B. Smith (University of Nottingham), University of Hertfordshire), P. Temi (NASA Ames Research Center), D. Wijesinghe (University of Sydney), and H-ATLAS/GAMA/GALEX teams

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

We present the properties of morphologically selected galaxies detected in the Herschel-ATLAS Science Demonstration Phase. Spiral galaxies are preferentially selected in our sample, and very few early-type galaxies (ETGS) are detected. We investigate the properties of a unique sample of blindly selected star-forming and dusty ETGs at submillimetre wavelengths. By comparing to a control sample of optically selected galaxies, we find 4 percent of ETGs contain enough dust to be detected by Herschel. The ETGs detected in H-ATLAS have more than an order of magnitude more dust than non-detected ETGs, for which we infer a median dust mass through stacking. We investigate whether the observed dust is from evolved stars, or has been acquired from external sources as a result of interactions and mergers.

Measuring the physical properties of galaxy components in modern multi-wavelength surveys

Author: Boris Haeussler

Univ. of Nottingham

Co-Authors: S.Bamford (Univ. of Nottingham), A.Rojas (Carnegie-Mellon Univ., Qatar)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

Most galaxies are fundamentally multi-component systems, often comprising a spheroidal bulge and a thin disk. As these components have largely independent origins, separating their properties provides important information with which to constrain models of galaxy formation and evolution. However, current automated methods are not sufficiently developed to allow the routine use of this technique on large samples of galaxies. In this talk we introduce the MegaMorph project, in which we are developing an accurate, robust tool for measuring the key physical quantities of the individual structural components of galaxies imaged by large multi-band surveys. The primary focus of our work is the extension of current tried-and-tested galaxy fitting/decomposition techniques (e.g. GALAPAGOS & GALFIT) to fully utilise multi-band imaging, as routinely produced by modern surveys, both ground-based (e.g. GAMA/SDSS) and space-based (e.g. CANDELS/HST). Using all the available multi-colour information in the galaxy fitting process enables much more robust decompositions in terms of physically-meaningful parameters. We will demonstrate how these enhancements allows us to examine the properties and evolution of galaxy components in previously unattainable detail.

Galaxies and AGN in the WISE survey

Author: Andrew Blain

University of Leicester

Co-Authors: WISE Science Team

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

The 4-band all-sky survey made by the Wide-Field Infrared Survey Explorer (WISE) mission in 2010 has just/will very soon make a preliminary data release at the time of the NAM. About 250 million mid-infrared selected objects are included. I will highlight the features of the survey, and some results from early extragalactic follow-up investigations by the science team, during the short and hectic proprietary period of the mission. With a 48-arcmin field of view and 1024x1024 detectors, WISE may well be the definitive all-sky infrared survey from 3-30 microns. The data for 55% of the sky is available, and can be accessed from the IRSA archive at IPAC: a catalogue and image search tool is/will soon be available.

The GAMA Multi-Wavelength Survey: The Stellar-Mass Halo-Mass Paradigm

Author: Aaron Robotham

University of St Andrews

Co-Authors: GAMA team (there will be a lot otherwise, so this is probably best)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

I discuss the latest aspects of the ongoing GAMA survey, a multi-wavelength survey (UV-Radio) centred around a large spectroscopic program based at the AAT. GAMA phase I has recently ended, producing 130K redshifts (98% completeness r<19.4) over 144 sq. deg. of sky. This data, coupled with GALEX, SDSS, UKIDSS data, allows us to model galaxy evolution both as a function of stellar mass *and* halo mass. The latter is possible through the creation of the highest fidelity group catalogue yet constructed, and allows us to probe down to local group scale halos. Thus GAMA is exploring galaxies in the most fundamental manner possible.

GAMA-SIGMA: Exploring Galaxy Structure Through Modelling

Author: Lee Kelvin

University of St Andrews

Co-Authors: S. P. Driver (University of St Andrews); D. T. Hill (University of St Andrews); A. S. G. Robotham (University of St Andrews); E. Cameron (ETH Zurich)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Talk

Summary:

The Galaxy And Mass Assembly project (GAMA) is a joint Anglo-Australian collaboration combining data from 5 ground-based telescopes, 3 space missions and 2 radio telescopes, ultimately using these data to explore galaxy formation and evolution on scales of 1kpc to 1Mpc. SIGMA (Structural Investigation of Galaxies via Model Analysis) is the structural analysis pipeline within GAMA designed to fit a 2D single-SÃ©rsic component to a catalogue of galaxies across multiple bands in a fully-automated and high-fidelity fashion, providing a measurement of the SÃ©rsic magnitude, SÃ©rsic index, half-light radius, position angle and ellipticity for every input galaxy. We present SIGMA results for ~150,000 GAMA main-survey galaxies modelled independently in optical-to-near-IR imaging data from the SDSS (ugriz) and UKIDSS-LAS (YJHK), and examine how their measured physical properties vary with wavelength. In addition, we further discuss the use of this dataset in exploring the relations between structure, colour, morphology, environment and stellar content, fully exploiting the possible scientific potential of the GAMA database.

A numerical/theoretical study of triggered star-formation

Author: SUMEDH ANATHPINDIKA

INDIAN INSTITUTE OF ASTROPHYSICS

Co-Authors:

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

The lifetime of molecular clouds (MCs) is typically of the order of a million years. MCs over this period, may be exposed to catastrophic events such as collision with other clouds, irradiation by a flux of ionising photons emitted by young OB stars, or possible interaction with dense shells driven by supernovae or shells associated with HII regions. In this talk, I propose to review my recent work on the possible outcome of these realisations with the aid of numerical simulations performed using the powerful particle-based, Lagrangian scheme, smoothed particle hydrodynamics (SPH).The simulations demonstrate that, commencing from a relatively quiescent cloud, an external trigger, as one of those listed above, could produce fractal structure in its interiors; stars could possibly form in the densest filamentary regions. While intercloud collisions are dissipative, I argue, evolution of the post-collision composite body depends on the precollision velocity of individual clouds. I also suggest that the relatively denser MCs irradiated by ionising radiation could be good demonstrative candidates of sequential star-formation, a scenario proposed by Elmegreen and others more than three decades ago. Finally I shall describe the spectrum for clumps condensing out of shocked gas slabs.

On the Origins of Compact Elliptical Galaxies

Author: Avon Huxor

University of Bristol

Co-Authors: S.Phillipps (Bristol); J.Price (Bristol)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

Compact elliptical (cE) galaxies are a rare type, exemplified by M32, exhibiting small effective radii and high mean surface brightnesses. Recent work has suggested that the most likely scenario for the formation of cEs is as a result of the tidal stripping of a more massive disk galaxy. Others, however, argue that they represent the low-mass end of the population of normal elliptical galaxies. We have undertaken a survey of SDSS DR7 (with follow-up observations) to identify cE candidates across a range of environments to try and address this issue. In this paper I will present two newly-found cEs in which we see the stripping in progress. "the smoking gun" of the stripping scenario. It is notable that both of these galaxies are found in very small galaxy groups, not the galaxy clusters in which cE have, for the most part, been hitherto sought. However, we have also found one example of an isolated cE, with no evidence of any disk or tidal features. It can not be the result of stripping, and may be a genuine low-mass elliptical. These three cEs show that at least two channels of formation are available.

The Halo Occupation Distribution since z=1.5

Author: Chris Collins

Liverpool John Moores University

Co-Authors: Diego Capozzi (LJMU); John Stott (Durham); Matt Hilton (Nottingham)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

We study the evolution of the Luminosity Function and Halo Occupation Distribution in 15 X-ray clusters between z=0.8-1.5 using Subaru near-IR imaging. We find that K* evolution is consistent with the semi analytic predictions of Bower et al (2006), with K* about 0.5 mag brighter than the corresponding field data. Both the counts of galaxies in clusters (N_) and the average cluster concentration index c_g=2.8+-pm0.9 of our sample agree with estimates of the same quantities from the Bower et al (2006) predictions, based on our own analysis of these well-matched mock clusters. This indicates that the current semi-analytic models provide an adequate description of the star formation and mass assembly history of most massive cluster galaxies at z=1. Further studies, particularly of the concentration parameter, are required at low and intermediate redshifts (z~0.5), where current datasets disagree.

Using Diffuse Interstellar Bands to Probe the Diffuse Interstellar Medium

Author: Mandy Bailey

Keele University

Co-Authors: J. Th. van Loon (Keele)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

Typically the Interstellar Medium (ISM) conditions are probed via lines arising from neutral or singly-ionized atoms or molecules. This poses a problem with understanding the nature of gas in high temperature environments such as the Local Bubble (LB) and environments of high ultraviolet radiation such as the Disc-Halo interface. To overcome these problems it is necessary to probe the ISM using species that may survive such conditions. This can be achieved using absorption in the so-called Diffuse Interstellar Bands (DIBs) whose carriers are large molecules such as polycyclic aromatic hydrocarbons (PAHs). Such molecules are thought to be resistant to UV radiation. Observations of DIBs have shown that they are sensitive to their environment with some known to exist in hot, UV-irradiated environments. The ratio of Î»5780/ Î»5797 equivalent widths is an indicator of the ionization conditions, with a high Î»5780/ Î»5797 ratio indicating the existence of interfaces between cool/warm and hot gas. Here we use the relative strengths of the Î»5780 and Î»5797 DIBs in the spectra of stars in the Solar Neighbourhood, globular clusters, and the Magellanic Clouds to map the small scale structure in the warm ISM.

Mapping The Outer Galaxy in CO and HI

Author: Lee Summers

Co-Authors: C. M. Brunt (University of Exeter)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

Using observations of the J=1-0 transition of CO from the Exeter-FCRAO Galactic Plane Survey and 21cm HI observations, from the Canadian and VLA Galactic Plane surveys, of the first and second Galactic quadrants of the Milky Way - I present a model of spiral structure (involving the Perseus and Outer spiral arms) with spatially convolved and resampled maps of these spiral arm regions, at constant linear resolution.

The Exeter-FCRAO Carbon Monoxide Survey of the Northern Galactic Plane

Author: Lee Summers

Co-Authors: C. M. Brunt (University of Exeter) J. C. Mottram (University of Exeter) M. H. Heyer (University of Massachusetts)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

Large scale Carbon Monoxide (CO) observations help us understand the structure and dynamics of the mass reservoir available for Galactic star formation. We observed the J(1-0) lines of 12CO and 13CO over a wide-latitude region between 141

The molecular gas properties as a function of galaxy activity

Author: Dr Estelle Bayet

University of Oxford

Co-Authors: M. Bureau (University of Oxford) S. Viti (UCL) D. Williams (UCL) A. Crocker (University of Massachusetts)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

The molecular gas physical properties namely its temperature, its volume gas density, etc as much as the molecular gas chemical properties such as the abundance ratio existing between its observed species, its state of ionisation, etc, are an essential knowledge to acquire for better understanding the process of star formation in external galaxies. So far, only few studies provide a comprehensive determination an analysis of such properties, most often performed at low resolution. With the forthcoming ALMA Interferometer which will help us reaching spatial scales in external galaxies up to a few pc, typical size of individual clouds, it is primordial to pursue and enhanced this effort . I will present in my talk the physical and chemical gas properties that I have obtained at low resolution for a sample of 10 nearby galaxy centers, showing the influence of the various type of galaxy activity or environmental characteristics on these properties i.e. starburst (SB), AGN, SB+AGN, Supernovae, low-metallicity, etc. I will also present for the first time some high-resolution maps recently acquired on a close galaxy (IC10) which starts unveiling the properties of the molecular gas at smaller scales. I will also present for the first time the physical properties obtained for the molecular gas observed in early-types galaxies, galaxies previously thought wrongly to be 'red-and-dead' systems in terms of star formation. I will conclude by enumerating the remaining interesting questions yet to be solved.

The Effect of the Large Scale Structure of the Galaxy on Star Formation Properties

Author: David Eden

Liverpool John Moores University

Co-Authors: T.J.T.Moore (Liverpool John Moores University)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

The Galactic plane at l=30Â° contains the tangent of the Scutum-Centaurus Arm and the near end of the Long Bar of the Galaxy. The Sagittarius Arm also runs across the field. We make use of the BOLOCAM Galactic Plane Survey and the Galactic Ring Survey to find the fraction of total gas mass in dense, 1.1mm continuum traced structures and to see how this fraction varies over this field; in relation to the proximity of large-scale structures and the local environment.

Studying the influence of magnetic fields in star formation with BLAST-Pol

Author: Lorenzo Moncelsi

Cardiff University

Co-Authors: P. Ade (Cardiff), F. E. Angile (UPenn), S. Benton (UToronto), E. Chapin (UBC), M. Devlin (UPenn), L. Fissel (UToronto), N. Gandilo (UToronto), J. Gundersen (UMiami), P. Hargrave (Cardiff), D. Hughes (INAOE), J. Klein (UPenn), A. Korotkov (Brown), G. Marsden (UBC), T. Matthews (NorthWestern), T. Mroczkowski (UPenn), B. Netterfield (UToronto), G. Novak (NorthWestern), D. Nutter (Cardiff), L. Olmi (U. Puerto Rico/INAF), E. Pascale (Cardiff), C. Quinn (Cardiff), G. Savini (UCL), D. Scott (UBC), J. Shariff (UToronto), J. Soler (UToronto), N. Thomas (UMiami), M. Truch (UPenn), C. Tucker (Cardiff), G. Tucker (Brown), D. Ward-Thompson (Cardiff), D. Wiebe (UBC).

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLAST-Pol) is a suborbital mapping experiment, designed to study the role played by magnetic fields in the earliest stages of star formation, via the polarised submillimetre emission from aligned elongated dust grains. BLAST-Pol is the reconstructed BLAST telescope, with the addition of linear polarisation capabilities. Using a 1.8m Cassegrain telescope, BLAST-Pol images the sky onto a focal plane of 280 bolometric detectors in three arrays at 250, 350, and 500 um, with a resolution of 30'' at 250 um. BLAST-Pol has just completed its first successful 10-day flight from Antarctica in December 2010, observing a dozen of Galactic molecular clouds with unprecedented combined mapping speed and resolution. The instrument provides a much needed bridge in spatial coverage between larger-scale, coarse resolution surveys and narrow field of view, high resolution observations of substructure within molecular cloud cores. The larger scale surveys in the optical/near-infrared measure absorption polarisation and hence only trace the low-extinction (Av~1-5), low-density edge regions of molecular clouds, while ground-based submillimetre polarimetry is only sensitive to the high-extinction (Av~10-100), high-density central regions of the clouds. BLAST-Pol is sensitive enough to detect polarised emission over a wide range of dust column densities, corresponding to Av >= 4.

12CO lines and LVG Model: NGC6946

Author: Selcuk Topal

Oxford Physics

Co-Authors: E.Bayet (Oxford Astrophysics), M.Bureau (Oxford Astrophysics)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

The understanding of molecular gas properties is essential to better constrain star formation processes in external galaxies. To determine the gas kinetic temperature (Tk), volume density (n(H2 )) and column density (N(CO)) of the molecular gas using non-local thermodynamic equilibrium models, it is necessary to obtain observations of multiple lines of 12CO. We present such a survey in the nearby galaxy NGC 6946, that includes a very high number of supernovae and has a star formation rate 10-15 times higher than our own Galaxy. We focus on two speciï¬c positions in spiral arms that covers three prominent star formation regions. We use the Leiden Atomic and Molecular Database for the collision rates and coefficients, the RADEX code for large velocity gradient (LVG) model calculations, and we apply Ï‡2 tests to choose the best models. We present our LVG model results for the two positions using at least four 12CO transitions, and also the radial distribution of molecular gas up to 5.6 kpc from the center using multiple pointings along a radial cut. Both positions include very warm and dense gas.

Analysing stellar motions and spiral arm formation in spiral galaxies

Author: Robert Grand

Mullard Space Science Laboratory (UCL)

Co-Authors: Daisuke Kawata, Mark Cropper

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

Spiral density wave theory (SDWT) states that the spiral pattern is a long lived wave structure, in that a spiral arm is analogous to the crest of a wave in the ocean; not necessarily consisting of the same stars as it evolves, but maintaining the high density of a wave peak. It also states that the spiral arms rotate at fixed (pattern) speeds, constant over radius and time. We run several N-body simulations of Milky Way size disk galaxies, and study how spiral arms develop and affect the motions of stellar particles throughout their lives. We find that the spiral arms are recurrent material features, and the pattern speed generally decreases with radius, in such a way that the pattern speed almost equals the rotation speed of stars at all radii. We demonstrate that such spiral arms induce strong radial migration of the stellar component and discuss how the orbits of stars are related to the recurrent nature of the spiral arms.

Chemodynamical evolution of M33 size disk galaxies

Author: Awat Rahimi

UCL - MSSL

Co-Authors: Daisuke Kawata

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

We are developing a new version of GCD+, an N-body/SPH chemodynamical code, to include powerful supernovae feedback and metal diffusion and new star formation and feedback recipes to keep the gas and stellar particle masses equal and constant. We simulate M33-size galaxies, and compare them with recent multi-wavelength observations. We set up an initial condition of an M33-like galaxy that comprises gas and stellar disk particles in a fixed dark matter halo gravitational potential. The simulations then follow about 2 billion years of evolution and include the effects of radiative cooling, star formation and chemical evolution. We discuss how the star formation rate, metallicity distribution and velocity dispersion of the gas components are affected by the modelling of star formation and feedback, comparing with recent observations.

Chemodynamical evolution of M33 size disk galaxies

Author: Awat Rahimi

UCL - MSSL

Co-Authors: Daisuke Kawata

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

We are developing a new version of GCD+, an N-body/SPH chemodynamical code, to include powerful supernovae feedback and metal diffusion and new star formation and feedback recipes to keep the gas and stellar particle masses equal and constant. We simulate M33-size galaxies, and compare them with recent multi-wavelength observations. We set up an initial condition of an M33-like galaxy that comprises gas and stellar disk particles in a fixed dark matter halo gravitational potential. The simulations then follow about 2 billion years of evolution and include the effects of radiative cooling, star formation and chemical evolution. We discuss how the star formation rate, metallicity distribution and velocity dispersion of the gas components are affected by the modelling of star formation and feedback, comparing with recent observations.

Galaxy And Mass Assembly: Independent Caustic Mass Measurements

Author: Mehmet Alpaslan

University of St Andrews

Co-Authors: A. Robotham (University of St Andrews); S. P. Driver (University of Western Australia)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

In this work, we use the caustic mass estimator to measure the dynamical masses of the GAMA groups. We will also compare these mass estimates to those obtained through a dynamical analysis of the groups.

A New Method to Determine the Star Formation Histories of Resolved Galaxies

Author: Emma Small

Liverpool John Moores University

Co-Authors: Dr. David Bersier (Liverpool John Moores University) Dr. Maurizio Salaris (Liverpool John Moores University)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

Resolved stellar populations in the Local Group enables the study of galaxy formation and evolution over cosmic time. In this talk, I will present a new maximum likelihood method to determine the complex star formation histories of stellar populations by fitting combinations of isochrones to a colour-magnitude diagram. The aim of the method is to determine the ages, metallicities, distance and reddening of the stellar population consistently and objectively. I will discuss tests completed using synthetic data to show the robustness of the technique and present results for the star formation history of the Carina dwarf galaxy.

A multi-wavelength study of AGN feedback in BCG

Author: Stephen Hamer

Durham University

Co-Authors: A.C.Edge (Institute for Computational Cosmology, Department of Physics, University of Durham, South Road, Durham DH1 3LE, UK) A.M.Swinbank (Institute for Computational Cosmology, Department of Physics, University of Durham, South Road, Durham DH1 3LE, UK)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

Brightest Cluster Galaxies have a central role in the regulation of cooling gas within the cores of clusters through an AGN feedback. This feedback mechanism is currently believed to be the main component preventing catastrophic cooling of gas within cluster cores. I will present multi-wavelength observations of Hydra-A and discuss the presence of a rotating disc within the BCG and central cluster region. The existence of this ordered rotation and its potential effects on AGN feedback within the BCG and cluster core will be discussed. I will also outline similar, though less complete, observations of a larger sample of BCGs and discuss how our results suggest that the processes evident in Hydra-A may be an important step in understanding the link between the cooling gas and the AGN at the centre of every BCG.

A multi-wavelength view of Star Formation in Nearby Galaxies

Author: Smriti Mahajan

UNIVERSITY OF BIRMINGHAM

Co-Authors: Matthew L.N. Ashby, Steven P. Willner, Giovanni G. Fazio (CfA); Somak Raychaudhury (University of Birmingham)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

We report the first outcomes from the Star Formation Reference Survey, a program designed to systematically elucidate the properties of nearby star forming galaxies. By controlling for total and specific star formation rate together with dust temperature, we have assembled a large (369) far infrared (FIR)-selected sample that is fully representative of all conditions under which star formation occurs in the local Universe. A rich dataset spanning multiple bands from the ultraviolet to the mid-infrared and into the radio is now being used to assess the reliabilty and systematics of the star formation rate (SFR) indicators commonly used in the literature. In this talk we show how SFR distributions derived from mutually independent data correlate with one another and with the total bolometric luminosity of the galaxy. Our results suggest that the global SFR for galaxies (spanning over five orders in luminosity) as expected from their bolometric luminosity can be derived using any single star formation tracer (FIR, 8.0 micron dust, FUV, NUV or 1.4 GHz radio continuum emission) within a factor of 1.5-4, such that the scatter in the correlation is a function of luminosity and galaxy type.

The effects of dust on the derived photometric parameters of disks and bulges in spiral galaxies

Jeremiah Horrocks Institute-University of Central Lancashire

Co-Authors: Cristina C. Popescu (Jeremiah Horrocks Institute-University of Central Lancashire), Richard J. Tuffs (Max Planck fur Kernphysik-Heidelberg), Anne E. Sansom (Jeremiah Horrocks Institute-University of Central Lancashire)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

Here we quantify the effects of dust on the derived photometric parameters of disks and bulges: disk scalelengths, central surface-brightness, axial ratios and bulge effective radii. The effects of dust are derived for both broad-band and narrow line (Balmer lines) images. The changes in the derived photometric parameters from their intrinsic values (as seen in the absence of dust) were obtained by fitting simulated images of disks and bulges produced using radiative transfer calculations and the model of Popescu et al (2011). This study follow on the analysis of Moellenhoff et al. (2006), who quantified the effects of dust on the photometry of old stellar disks seen at low and intermediate inclination. Here we extend the study to disks at all inclinations and we also investigate the changes in the photometry of young stellar disks and bulges. We find that dust effects on all structural parameters of disks and bulges are significant and strongly increase with inclination and dust opacity.

Anatomy of an early-type minor merger: a WFC3 and SAURON study of NGC 4150

Author: Sugata Kaviraj

Imperial College London

Co-Authors: R. M. Crockett (University of Oxford); R. W. O'Connell (University of Virginia); J. Silk (University of Oxford); R. Windhorst (Arizona State University); B. Whitmore (Space Telescope Science Institute); M. Cappellari (University of Oxford); M. Bureau (University of Oxford); R. L. Davies (University of Oxford); S. K. Yi (Yonsei University)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

A significant recent discovery, using ultraviolet (UV) survey data, is the widespread presence of low-level star formation in nearby early-type galaxies (ETGs), plausibly driven by gas-rich minor mergers. Combining the unprecedented UV capabilities of HSTâ€™s new Wide Field Camera 3 (WFC3) with integral-field spectroscopy from SAURON, we perform a detailed, spatially-resolved analysis of young stars and their kinematics in NGC 4150, a nearby star-forming ETG. A 'pixel-by-pixel' analysis in five WFC3 filters, spanning UV to i-band, reveals a central 0.9 Gyr old young stellar population, with a median metallicity of 0.5 solar, that contributes 3% of the stellar mass and is created by a minor merger with a mass ratio of ~1:20. Comparison to the SAURON kinematics demonstrates that the young stars also form a kinematically-decoupled core in the central 1/4 Re of the galaxy. While survey data has quantified the broad characteristics of star formation in the ETG population, spatially-resolved analyses, such as the one presented here, can strongly constrain the star formation and kinematical evolution on a galaxy-by-galaxy basis, making them highly desirable for a thorough understanding of ETGs at late epochs. This work was the subject of a recent Hubble press release: http://hubblesite.org/newscenter/archive/releases/2010/38/.

Radiative transfer modelling of galaxies in the epoch of SPICA

Author: Dr. Cristina C. Popescu

University of Central Lancashire

Co-Authors: Richard J. Tuffs (Max Planck Institut fuer Kernphysik, Heidelberg, Germany) and the SPICA/SAFARI consortium

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

We are living in an era of ever better and deeper wide-field optical surveys which have revealed a large population of translucent systems - the population of normal spiral galaxies. However, the majority of the spiral galaxies seen in these surveys do not have information on dust emission, which is essential for a complete characterisation of these systems. Here we highlight the huge potential of the next generation Space Infrared Telescope for Cosmology and Astrophysics (SPICA) in detecting statistical samples of local Universe low luminosity spiral galaxies. We also report on recent progress on radiative transfer modelling of these galaxies, which is a prerequisite for deriving intrinsic physical parameters from their panchromatic spectral energy distributions.

In search for new bulge classification scheme

Author: Christina Gao

Oxford University

Co-Authors: I.K.Soechting (University of Oxford); A.E.Sansom (University of Central Lancashire)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

In this investigation we studied a sample of 42 nearby galaxies with their g- and r- band images obtained with the GMOS instruments at the Gemini Observatory. We used Galfit 3.0, a two-dimensional fitting tool, to model the surface brightness profile and simultaneously decompose the bulge and disk for each galaxy. We found that the conventional bulge-disk structure did not apply to every single galaxy in our sample and that some of the galaxies required a double bulge fitting at the centre. The results imply that a simple division into bulges and pseudo-bulges might not reflect the true complexity of bulge morphologies. Our sample also benefits from the high signal-to-noise spectra, which will allow us, in the future, to cross examine our findings with the metallicity and age distribution.

Line Contamination in the SCUBA-2 Continuum Data

Author: Emily Drabek

University of Exeter

Co-Authors: J. Hatchell (University of Exeter)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

Observations of the dust emission using bolometer arrays can be contaminated by molecular line flux, such as the flux from 12CO. It is important to quantify the contribution of CO flux to the continuum flux in order to distinguish between observations of fainter objects with higher sensitivity detectors and contamination to the dust continuum bands due to molecular lines. The conversion factors for CO line integrated intensities were calculated for the SCUBA-2 bands and applied to HARP 12CO maps of ngc1333 in the Perseus complex in order to calculate the contribution of CO to the dust continuum.

Planck Early Results: New Light on Anomalous Microwave Emission from Spinning Dust Grains

Author: Michael Peel

Jodrell Bank C. for Astrophysics, University of Manchester

Co-Authors: Planck collaboration: Ade et al.

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

The Planck collaboration have recently announced the first science results from the mission, looking at foreground emission from our Galaxy. This talk will summarise the results from the first Planck science paper on Anomalous Microwave Emission (AME). Planck has revealed the high frequency part of the AME spectrum from the Perseus and Rho Ophiuchus molecular clouds for the first time, and found that the most precise measurements to date of this effect are well fitted using spinning dust grain models. This is a new emission mechanism that has been discovered in the last 15 years, which peaks at wavelengths of around 1cm (30GHz). In Perseus, spinning dust in the dense molecular gas can account for most of the AME; the low density neutral gas appears to play a minor role. In Rho Ophiuchus, the ~30 GHz peak is dominated by dense molecular gas, but there is an indication of an extended tail at frequencies 50-100 GHz, which can be accounted for by irradiated low density atomic gas. The discovery of two new regions of AME from a search of the Planck 28.5GHz map was also reported, which were again well fitted by spinning dust models.

The stability of low surface brightness disks based on multi-wavelength modeling

Author: john MacLachlan

University of St Andrews

Co-Authors: L.D. Matthews (Harvard-Smithsonian Center for Astrophysics); K. Wood (University of St Andrews); J.S. Gallagher (University of Wisconsin)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

To investigate the structure and composition of the dusty interstellar medium (ISM) of low surface brightness (LSB) disk galaxies, we have used multiwavelength photometry to construct spectral energy distributions for three low-mass, edge-on LSB galaxies (Vrot= 88 to 105 km/s). We use Monte Carlo radiation transfer codes that include the effects of transiently heated small grains and polycyclic aromatic hydrocarbon molecules to model and interpret the data. Our results indicate that unlike the high surface brightness galaxies previously modeled, the dust disks appear to have scaleheights equal to those of the stellar disks. This result supports the findings of previous studies that low mass disk galaxies have larger dust scale heights and suggests that the cold ISM of low mass, LSB disk galaxies is stable against fragmentation and gravitational collapse along spiral arms. This may help to explain the lack of observed dust lanes in edge-on LSB galaxies and their low current star formation rates.

Investigations of dust heating in M81, M83, and NGC 2403 with Herschel and Spitzer

Author: George Bendo

University of Manchester

Co-Authors: Herschel-SPIRE Local Galaxies Guaranteed Time Program

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

We use Herschel Space Observatory and Spitzer Space Telescope 24-500 micron data along with ground-based optical and near-infrared data to understand how dust heating in the nearby face-on spiral galaxies M81, M83, and NGC 2403 is affected by the starlight from all stars and by the radiation from star forming regions. We find that 70/160 micron flux density ratios tend to be more strongly influenced by star forming regions. However, the 160/250, 250/350, and 350/500 micron flux density ratios are more strongly affected by the light from the total stellar populations, suggesting that the dust emission at >160 microns originates predominantly from a component that is colder than the dust seen at <160 microns and that is relatively unaffected to star formation activity. We conclude by discussing the implications of this for modelling the spectral energy distributions of both nearby and more distant galaxies and for using far-infrared dust emission to trace star formation.

Evolution of high redshift galaxies, QSOs and sub-mm sources

Author: Tom Shanks

Durham University

Co-Authors: M.D. Hill (Durham University); N. Metcalfe (Durham University); N. Nikoloudakis (Durham University)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

We argue that the phenomenology of galaxy and QSO evolution may be simpler when separated from the expectations of theoretical modelling. Thus we first use the COSMOS field photo-z of Ilbert et al (2009) to test the galaxy pure luminosity evolution model of Metcalfe et al (1996). We find good agreement between this model's predictions and the luminosity functions of red and blue galaxies out to z=2. This implies that early types have only passively evolved over this look-back time while the surface brightness of late types has brightened significantly but with little impact of galaxy merging in either case. We next suggest that the lack of early-type evolution taken together with the luminosity independence of QSO clustering and the pure luminosity evolution of the QSO LF may imply that QSOs are long-lived and that the prime epoch of black-hole growth was at z>2. Finally, we show that this simple picture of galaxy and QSO evolution can also accurately predict number count and redshift distributions in the X-ray, Spitzer, Herschel and SCUBA bands. We briefly discuss the implications for theoretical galaxy formation models.

The VLT LBG Survey

Author: Rich Bielby

Durham University

Co-Authors: T. Shanks (Durham University), P. Tummuangpak (Durham University), N. Crighton (MPIA), L. Infante (Pontifica Universidad Catolica de Chile)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

We have completed the largest spectroscopic survey of Lyman-break galaxies (LBGs) to date using the wide field of VLT VIMOS. In total, the survey consists of over 2,000 galaxy redshifts over the range 23 quasars). In addition we have complimented the VLT data with AAOmega spectra of R<22 z>2 QSOs in each of our survey fields. Using the LBG spectra, we find evidence confirming the outflowing nature of the gas within LBGs via the offsets (~600km/s) in the emission and absorption rest-frame UV lines. Further to this, we use the LBG data to investigate the large scale structure at z = 3 via the galaxy auto-correlation function, finding an LBG clustering strength of r0 = 3.19 h-1 Mpc, equivalent to these galaxies residing in dark matter halos of mass M ~ 10^11 Msolar. Finally, we combine the LBG redshift and QSO absorption line data to investigate the relationship between gas and galaxies at z=3 and find evidence for the correlation of LBGs with increased densities of HI and CIV.

Attractors in phase-space of stellar systems under impulses

Author: Jeremy Barber

University of St. Andrews

Co-Authors: H. Zhao (University of St. Andrews); X. Wu (Max Planck Institute)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

We examine the effects for impulses on to a star cluster or a galaxy via controlled N-body simulation, and examine if they converge to fixed points in certain space of dynamical parameters independent of initial condition and the assumption of the gravity theory. We check especially the finding of Hansen et al. (2010) that the final states all live on a narrow line in the radial pressure gradient vs. anisotropy plane. We vary the recipes for impulses to examine if there are multiple attractors.

Build it up, tear it down: Star formation in the Galactic centre

Author: W. E. Lucas

University of St Andrews

Co-Authors: I. A. Bonnell (University of St Andrews)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

Observations of the Galaxyâ€™s centre have revealed the existence of two discs or possibly streamers of O and W-R stars orbiting Sgr A* at radii between about 0.05 and 0.5 pc and at an angle approaching 90Â° to one another. This would seem to indicate that two separate star-forming events have taken place around the black hole, yet the stars appear to be coeval which points instead to a single event â€“ something of a problem. Here we use smoothed particle hydrodynamics (SPH) to show it is possible to create two star-forming gaseous discs at large angles from one another from a single turbulent cloud.

Wide field Imaging of the Hubble Deep Field using MERLIN and e-MERLIN

Author: Nick Wrigley

Jodrell Bank Centre for Astrophysics

Co-Authors:

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

The Hubble Deep Field has been an area of intense study since the initial observations were made by the HST in the mid '90s. Making equivalent wide-field high resolution observations of these distant galaxies at radio wavelengths requires the use of interferometers such as MERLIN, but these introduce issues characteristic of such instruments. Several issues are explored which can be minimised yielding some of the widest high resolution images to date. The results may have important implications for future wide-field imaging using e-MERLIN.

The Tully-Fisher Relation of Early-Type Galaxies

Author: Martin Bureau

University of Oxford

Co-Authors: T.A.Davis (University of Oxford); M.J.Williams (University of Oxford); Michele Cappellari (University of Oxford)

Session: GAL: Physics of galaxies at high and low redshift (includes Milky Way)

Presentation type: Poster

Summary:

The Tully-Fisher (luminosity-rotation velocity) relation of disk galaxies is commonly used to provide constraints on their formation and evolution. Unusually, we focus here on early-type galaxies, with significant pressure support. First, based on stellar kinematics and near-infrared imaging, we present detailed stellar dynamical models of a sample of 14 lenticular (S0) and 14 spiral galaxies, yielding both stellar and dynamical mass-to-light ratios. The observed Tully-Fisher relation of the S0 galaxies is found to be 0.5 magnitudes fainter than that of spirals at K-band, and unexpectedly this difference persists when the modeled dynamical masses are used. This implies that lenticular galaxies are not simply faded spirals (the most popular hypothesis), and that they must be 20% more compact at a given rotation velocity. Second, we show that CO is an excellent tracer of the rotation velocity in the numerous molecular gas-rich early-type galaxies. This allows to measure the Tully-Fisher relation of early-types in a straightforward manner, bypassing time-consuming stellar observations and modeling. The observed CO Tully-Fisher relation is consistent with the stellar one, but extends its applicability to all early-type galaxies with significant specific angular momentum (fast-rotators), including elliptical galaxies. Equally important, using the new generation of mm/sub-mm telescopes (e.g. ALMA), the CO Tully-Fisher relation offers a new simple tool to probe the mass-to-light ratio evolution of early-type galaxies to high redshifts.

Hard X-ray solar flare observations as diagnostic of electron transport in the chromosphere

Author: Marina Battaglia

University of Glasgow

Co-Authors: E. P. Kontar (University of Glasgow)

Session: HEP: High energy particles in the solar system

Presentation type: Talk

Summary:

The majority of solar flare hard X-rays come from the low solar atmosphere yet the structure of the chromosphere and the particle dynamics there is poorly understood. In the traditional flare model electrons accelerated in the corona precipitate along magnetic loop field-lines to the chromosphere where they lose their energy in coulomb collisions producing hard X-ray bremsstrahlung in the process. Using observations of solar flare footpoints made with the Ramaty High Energy Spectroscopic Imager (RHESSI) we determine the radial positions and sizes of footpoints as a function of photon energy in six flares to investigate the transport of flare accelerated electrons and the properties of the chromosphere. Assuming collisional thick-target transport, hard X-ray sources are located between 600 and 1200 km above the photosphere. The vertical sizes (along the path of electron propagation) are up to a factor 4 larger than predicted by the thick-target model, suggesting that additional effects such as magnetic mirroring and collisional pitch angle scattering have to be considered. We will discuss results from numerical simulations that include those processes and show how this affects the source sizes.

Nonlinear acceleration of relativistic electrons with electron cyclotron waves

Author: Dr Maxim Ponomarev

University of Sheffield

Co-Authors: Eun-jin Kim (University of Sheffield)

Session: HEP: High energy particles in the solar system

Presentation type: Talk

Summary:

Computational and theoretical analyses are performed to investigate optimal configuration for wave propagation to enhance the acceleration of electrons when the lower amplitude secondary electromagnetic waves cross primary wave in magnetised plasma. Firstly, computational method is based on numerical solution of relativistic Hamiltonian equations for an ensemble of electrons in time-dependent electromagnetic waves to increase the acceleration of electrons. Accuracy test has been implemented with redundant evolution equation for the Hamiltonian, which indicates less than 0.001% error. Secondly, physical mechanism for this enhancement is proposed by developing resonance moment method (RMM) based on the flow moment approximations by calculating moments-integrals inside the resonance layers. As an application of our developed RMM and general computation model, optimal configurations were proposed for the novel two-wave scheme in which the secondary wave is launched perpendicular to the external magnetic field. Numerical computation confirms that such a configuration can increase the mean electron velocity by one order of magnitude compared to the (conventional) one-wave configuration. This is a very promising result because the amplitude of the secondary wave is 10 times smaller than the one of the primary wave. The results are applicable to experiments in planetary magnetospheres, ionospheres as well as in magnetic fusion (M.Ponomarev, D.Carati, Advances in Space Research, 38, 1576-1581, 2006).

Particle acceleration by magnetic reconnection in twisted coronal loops

Author: Mykola Gordovskyy

University of Manchester

Co-Authors: Philippa Browning

Session: HEP: High energy particles in the solar system

Presentation type: Talk

Summary:

Photospheric motions may lead to twisting of the coronal magnetic field. Subsequent relaxation of magnetic field to a linear force-free configuration would result in free energy release. Browning & Van der Linden (2003) suggested that such a relaxation event can be triggered by onset of ideal kink instability. In the present work we consider a time-dependent model of magnetic reconnection in a twisted magnetic fluxtube and resulting proton and electron acceleration with a focus on field convergence near the fluxtube footpoints. We discuss temporal evolution of proton and electron energy spectra and possible observational implications.

Solar flares and X-ray polarisation - deducing related electron properties

Author: Natasha Jeffrey

University of Glasgow

Co-Authors: E.P.Kontar (University of Glasgow)

Session: HEP: High energy particles in the solar system

Presentation type: Talk

Summary:

In the Sun's atmosphere, flare events can produce high energy electrons (>10 keV) that propagate into the solar chromosphere producing hard X-ray (HXR) photons via bremsstrahlung. These energies are high enough that HXR photons emitted away from the Sun will propagate freely into interplanetary space while most of those emitted sunward will pass unhindered into the photosphere where they may be absorbed or Compton scattered. This Compton scattering leads to a 'reflected' albedo component that is observed in conjunction with the primarily produced bremsstrahlung component, and hence leads to an alteration in the observed HXR emission, greatest at peak scattering energies of 20-50 keV. Amongst other properties, the albedo component produces an alteration to the polarisation of the HXR source, a property that is highly dependent on the directivity of the HXR distribution and hence the the parent electron distribution produced by the flare. From our initial simulation results which model the above, I wish to discuss how the polarisation of an HXR source might be able to help predict the the high energy cutoff in the electron distribution and discuss how the polarisation across a single HXR source at one location on the solar disk varies spatially, with both the true bremsstrahlung and albedo component polarisations providing valuable insight into the flare accelerated electrons, important not only for understanding our own star but many high energy processes across the Universe.

Solar energetic particle transport across the interplanetary magnetic field

Author: Silvia Dalla

University of Central Lancashire

Co-Authors: J.Kelly (University of Central Lancashire); T.Laitinen (University of Central Lancashire)

Session: HEP: High energy particles in the solar system

Presentation type: Talk

Summary:

Solar energetic particles (SEPs) released during flares and CMEs propagate through the highly variable and turbulent interplanetary magnetic field (IMF) to reach heliospheric locations, eg near the Earth. The degree to which transport across the average magnetic field contributes to the propagation, and therefore to the measured SEP intensities, is currently the focus of many observational and theoretical studies. This presentation will discuss multi-spacecraft observations which point towards cross-field transport playing an important role. It will review several physical mechanisms that might be responsible for such transport, including the random walk of IMF lines and scattering due to turbulence. Results of test particle modelling of proton propagation from the Sun to Earth's orbit will be discussed.

How does the coronal magnetic topology relate solar activities to in-situ electron streams?

Author: Chuan Li

Mullard Space Science Laboratory

Co-Authors: Sarah Matthews, Christopher J. Owen, Lidia van Driel-Gesztelyi, Jian Sun

Session: HEP: High energy particles in the solar system

Presentation type: Talk

Summary:

Non-thermal electrons are one population of particles produced by rapid release of magnetic energy during solar activities. It is generally agreed that the impulsive keV electrons are originated from flaring active regions (ARs), while the gradual or major MeV electrons are coronal mass ejection (CME)-shock-related. Apart from dependence due to acceleration mechanisms and interplanetary transport effects, one viewpoint is that the coronal magnetic topologies might also contribute to the in-situ solar energetic particle (SEP) dynamical discrepancies. Firstly, we present the investigation of acceleration source of an impulsive electron event. Our analysis convincingly confirm that the jet in association with hard X-ray (HXR) flare and type III radio burst is a key to understand the production of beam-like electrons. The coronal magnetic topology in the source region is favorable for the jet formation, and consistent with the in-situ electron pitch-angle distribution (PAD). Then, we present the statistical survey of the major electron events. A significant link has been established between the coronal magnetic topology and the in-situ electron dynamics, e.g., timing and spectra.

Simulating the energetics of impulsive solar electron beams

Author: Hamish Reid

LESIA, Observatiore de Paris

Co-Authors: E. Kontar (University of Glasgow)

Session: HEP: High energy particles in the solar system

Presentation type: Talk

Summary:

Impulsive solar electron beams are able to be detected both in-situ near 1 AU and through their electromagnetic emission in the radio frequency â€“ known as type III radio bursts. Whilst the radio emission does not constitute a large amount of the electron beam energy, the production of Langmuir waves has a substantial effect on beam energetics. We self-consistently simulate an electron beam travelling from the Sun to the Earth taking into account the generation of Langmuir waves in an inhomogeneous background plasma. We find that the electron beam loses a substantial fraction of its energy after leaving the corona due to the density fluctuations of the heliospheric plasma. We also show how the spectrum of the electron beam develops radially from an initial single power-law distribution into a broken power-law observed near the Earth.

Cross-field transport of non-thermal electrons in thick target coronal loops

Author: Nic Bian

Glasgow University

Co-Authors: E. Kontar, I. Hannah

Session: HEP: High energy particles in the solar system

Presentation type: Poster

Summary:

Turbulence is thought to be involved in various physical processes that occur during solar flares and it is now possible to use RHESSI observations of Hard-X ray emitting electrons to estimate the magnitude of the magnetic field line diffusion in dense coronal loops. Our aim is to discuss the cross-field transport of non-thermal electrons resulting from the presence of broadband magnetic fluctuations in coronal loops. It is shown that a substantial variation in the level of magnetic fluctuations, that can be inferred from the observations, is possible whether the regime of transport is quasi-linear or non-linear.

Electron Anisotropy in Solar Flares

Author: Ewan Dickson

University of Glasgow

Co-Authors: E.Kontar (University of Glasgow)

Session: HEP: High energy particles in the solar system

Presentation type: Poster

Summary:

The angular variation of high energy electrons during a solar flare is key to understanding the acceleration mechanism. High resolution X-ray spectra observed by RHESSI (Ramaty High Energy Solar Spectroscopic Imager) can be used to estimate this anisotropy. The effect of photospheric albedo, Compton scattering of X-ray photons from the photosphere, should greatly influence the observed spectrum if the X-ray emitting electrons are highly beamed. The observed spectra will thus contain signatures of the anisotropy. The technique of regularised inversion is used to determine the proportion of the electron flux directed downwards towards the photosphere compared to the electron flux directed towards the observer. The RHESSI flare database has been searched and analysis performed on all flares found to have statistically significant counts above 300 keV. In total 9 flares suitable for analysis were found. The anisotropy of these flares both over the entire impulsive phase and for shorter time intervals was measured and the flares have all been found to exhibit angular distributions which is close to isotropic.

Particle acceleration in 3D self-consistent solutions of the MHD equations

University of Manchester

Co-Authors: P.K.Browning (Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK p.browning@manchester.ac.uk); S.Dalla (Jeremiah Horrocks Institute, University of Central Lancashire, Preston, United Kingdom; sdalla@uclan.ac.uk)

Session: HEP: High energy particles in the solar system

Presentation type: Poster

Summary:

Studies of hard X-ray emission in solar flares suggest a large proportion of flare energy is released in the form of non-thermal accelerated particles. It is well accepted that magnetic reconnection plays a significant role in the release of stored magnetic energy in flares, and thus the electric fields associated with reconnection are a prime candidate as a mechanism for accelerating charged particles. Particle acceleration has been studied in some detail within 2D reconnection geometries, using a test particle approach. However, 3D geometries are more relevant to the solar corona, and it is likely that 3D magnetic null points are common in the corona. Some progress has been made using test particle models studying particle acceleration in fields from numerical MHD simulations or analytical models of the outer (ideal) region of 3D reconnecting nulls. Here, we consider particle acceleration using background fields from self-consistent, analytic solutions of the MHD equations (e.g. Craig and Fabling, 1995), which model both the ideal and resistive regions of reconnection. Particle trajectories are analysed in detail, and energy spectra are calculated. The results are compared with the simpler models considered by Dalla and Browning (2005), which incorporated only the ideal region.

Effect of self-induced electric field on Langmuir turbulence generated by electron beams in flares

Author: Prof. Valentina Zharkova

Co-Authors: V.V.Zharkova (University of Bradford, UK) and T.V. Siversky (L'viv University, Ukraine)

Session: HEP: High energy particles in the solar system

Presentation type: Poster

Summary:

The precipitation of an electron beam injected into the solar atmosphere is studied for generation of Langmuir wave turbulence in the presence of collisional and Ohmic losses. It is found that at upper atmospheric levels the self-induced electric field suppresses the generation of Langmuir turbulence to very small regions below injection. With further precipitation into deeper atmosphere the initial single power law distributions of beam electrons are transformed into energy distributions with maxima at lower energies formed by collisional and Ohmic energy depletion. The electrons with lower energies (<20 keV) generate on large spatial scales intense low-hybrid and high-hybrid Langmuir waves with well defined patterns in the corona while higher energy electrons generate moderate low hybrid waves in the chromosphere. The self-induced electric field reduces the level and makes narrower the regions with low-hybrid Langmuir turbulence in the corona and upper chromosphere. High-hybrid Langmuir waves are found to be generated only by a very intense electron beam with the number of patterns being significantly reduced by the self-induced electric field.

Energetic particles at the Chromosphere

Author: Rim Turkmani

Imperial College

Co-Authors: J. C. Brown (University of Glasgow)

Session: HEP: High energy particles in the solar system

Presentation type: Poster

Summary:

With the solar chromosphere revealing itself as a very dynamic and complex region, and with new particle acceleration models that point at the Chromosphere as a major player in energizing accelerated particles (Brown et al 09), a new look at the chromosphere from the particle acceleration point of view is needed. Here, we take a closer look at the solar chromosphere and identify the requirements for energizing particles in this region and the possible mechanisms which are able to provide these requirements. Moreover, we look at the energy budget of solar flares and active regions and see how it changes if the chromosphere is incorporated in this budget as more than just an energy-loss area as it is generally viewed. A new picture emerges that explain many of the paradoxes which stem from the assumption that particles are only accelerated at the corona.

Photospheric signatures of eruptive events

Author: Ehsan Pedram

UCL Mullard Space Science Laboratory

Co-Authors: Sarah Matthews (MSSL)

Session: HEP: High energy particles in the solar system

Presentation type: Poster

Summary:

The connections between the site of explosive energy release in the corona and the lower atmosphere remain poorly understood, but hold great potential for understanding eruptive phenomena on the Sun. Herewe focus on the question of the existence of detectable signatures of an equal and opposite downward force during the eruption of a CME. In this context we look for evidence of changes in the photosphere and examine their association with coronal dimmings and so-called EIT waves. We make use of Hinode SOT data to anaylse small scale magnetic field changes at the onset of a flare and the CME, and compare these with coronal observations from SOHO, Hinode and SDO. We interpret these observations in the context of current eruptive flare models.

Development of Large Optics Capability in North Wales

Author: D.D Walker

UCL, Glyndwr University and Zeeko Ltd

Co-Authors: P. Harris, P. Rees, R. Evans, M. Parry-Jones, S. Hamidi (OpTIC-Glyndwr Ltd), G. Yu (Glyndwr University), C. Atkins, H-Y Li (UCL), J. Mitchell (Cranfield University, W. Messalink (Zeeko Ltd)

Session: IND: Astronomy, space and industry

Presentation type: Talk

Summary:

We report on the development of UK capability in large optics fabrication. In particular, we focus on the UK National Facility for Ultra Precision Surfaces at OpTIC-Glyndwr, less than 20 miles east of Llandudno. This Facility was established in 2005 as a university/industry collaboration, undertaking R&D in optical fabrication at the 1-metre scale using modern computer-controlled processes. More recently, ESO awarded a contract to manufacture seven prototype segments for the 42m E-ELT. This has stimulated substantial new investment in the design, construction and installation of production and metrology equipment with a capacity of 1.6m, including modification to the building to accommodate a 10m test tower. We describe the R&D programme, the Pilot Segment Facility, our goal of establishing a significant industry in North Wales, and how this could support the requirements of major science projects.

Terrestrial Uses Of FIR Astronomical Technology

Author: Ken Wood

QMC Instruments Ltd.

Co-Authors:

Session: IND: Astronomy, space and industry

Presentation type: Talk

Summary:

The UK can boast some of the worlds leading astronomical research groups. Astronomy represents one of the most demanding fields of scientific endeavour in terms of the performance requirements of instrumentation and this is certainly the case in FIR and mm-wave astronomy. Interest in the mm-wave and IR regions of the electromagnetic spectrum (known now as the Terahertz region)has never been higher. The race is on to produce new devices and techniques that will bring something to bear on quality of life issues like health, communications and security. I shall show how one UK company and its academic partners are applying FIR astronomical detection know-how to a range of non-astronomical applications.

Gaia: a textbook case of collaboration between industry and academia

Author: Mark Cropper

Mullard Space Science Lab, UCL

Co-Authors:

Session: IND: Astronomy, space and industry

Presentation type: Talk

Summary:

ESA's Gaia mission to study the dynamics and chemical evolution of the Galaxy, is due for launch in less than 2 years. This technical tour-de-force has been realised through a close cooperation between academic groups, aerospace engineering firms across Europe, detector and software specialists. This talk provides an overview of that activity and examines how well it has worked.

A report on space weather risks for business

Author: Mike Hapgood

RAL Space

Co-Authors:

Session: IND: Astronomy, space and industry

Presentation type: Talk

Summary:

The past year has seen growing awareness of the risks posed by space weather. Those risks range from nuisance impacts that perturb business systems to extreme events that threaten the resilience of our technological civilisation. The latter attracts much media hype but is a serious risk that is being studied at governmental levels in the UK and other countries. The former is a more subtle issue that is important for a wide range of industries including power, space, aviation, insurance and financial services. It is the subject of a recent report commissioned from RAL Space by Lloyds 360 Risk Insight, part of Lloyds insurance that briefs industry on emerging risks. This talk will outline the content of the report and discuss how it has been received by industry and by other organisations. It will stress the importance of linking the science to both the impacts of space weather and to practicable methods for mitigation. It will also discuss ways in which further economic impact can be developed and of the opportunities this provides across the RAS community: most obviously in solar and solar-terrestrial physics, but also embracing elements of solid-earth geophysics and stellar physics.

ATMOP: A better drag model through indices and assimilation

Author: Timothy Spain

UCL

Co-Authors: N. SÃ¡nchez-Ortiz (Deimos); C. LathuillÃ¨re (CNRS); J.-J. Valette (CLS); D. Jackson (Met Office); S. Bruinsma (CNES); A. Aylward (UCL); ATMOP Consortium

Session: IND: Astronomy, space and industry

Presentation type: Talk

Summary:

The ATMOP (Advanced Thermosphere Modelling for Orbit Prediction) is an EU Framework 7 project aimed at producing a new thermospheric model (DTM) with a focus on orbital air drag. Accurate air drag computation is essential to the monitoring and tracking of objects in the upper atmosphere, both in low-Earth orbit and on re-entry. The response of the atmosphere to Solar and geomagnetic activity is both very rapid and hard to predict, hence precise orbit determination requires accurate spatial and temporal nowcasting of the thermosphere. At present, Europe has neither a near-real-time thermospheric model nor operational services to provide regular thermosphere fore- and nowcasting. The UCL CMAT2 model will be used as the scientific basis of the empirical model, using data assimilation to mediate between the available data and the parameters required to develop the drag model itself.

The UK Space Science and exploration Programme: Science Enabled by Technology

Author: David Parker

UK Space Agency

Co-Authors:

Session: IND: Astronomy, space and industry

Presentation type: Talk

Summary:

The UK's involvement in space science is driven by the relationship between researchers and technologists and between universities and industry. The trend to closer working across the space sector is a focus of the UK Space Agency. Past and future programmes designed to extract the maximum value out of the UK's investment will be discussed along with some examples of successes that have been achieved. The recently published National Space Technology Roadmaps will also be outlined.

Switching States in Pulsar Magnetospheres

Author: Prof Andrew Lyne

University of Manchester

Co-Authors:

Session: MAG: Magnetospheres and ionospheres throughout the Universe

Presentation type: Talk

Summary:

Switched instabilities in the radiation from pulsars on timescales of seconds to hours have been observed in many pulsars since shortly after their discovery. Recently, a review of the long-term timing behaviour of pulsars at Jodrell Bank has shown that timing noise, smooth changes in the rotation rate of a pulsar, often results from typically two different spin-down rates. Pulsars switch abruptly between these states, often quasi-periodically, on timescales of between months and years. We show that for several pulsars the spin-down rate is correlated with changes in pulse shape, indicating that timing noise has its origin in instabilities in the magnetosphere, and not within the superfluid components of the neutron star interior. We now see that many pulsar phenomena, including mode-changing, nulling, pulse-shape variability and timing noise are therefore all linked and caused by changes in the pulsar magnetoshpere. This understanding offers the possibility of removing timing noise and turning pulsars into even better clocks for astrophysical studies of gravitation.

Post-Equinox Saturn Magnetic Rotation

Author: David SOUTHWOOD

European Space Agency

Co-Authors:

Session: MAG: Magnetospheres and ionospheres throughout the Universe

Presentation type: Talk

Summary:

During late 2009 and 2010 the Cassini spacecraft remained in a low latitude orbit providing a good platform for analysis in the inner magnetosphere of the periodic magnetic signals associated with planetary rotation. The epoch immediately follows the Saturn equinox. During the time in question it has already been reported that the periods of the northern and southern SKR radio signals appear to come together whilst the mean frequency appears fairly stationary. Here we report on analysis of what happens to the corresponding periodic magnetic signals seen by the spacecraft. It is shown that the period signals in the magnetic field have a fixed primary period of close to 642.3 minutes during the period in question matching well the period corresponding to the mean radio frequency. It is also shown that rapid changes in phase of order half a cycle take place between periapsis passes. It is argued that in contrast with earlier analyses before equinox where the Southern period dominated it would seem now that Northern and Southern amplitudes are now about equal. The nature of the underlying magnetospheric signal structure will be discussed.

Author: Evan Keane

Co-Authors:

Session: MAG: Magnetospheres and ionospheres throughout the Universe

Presentation type: Talk

Summary:

In 2006, eleven transient radio neutron stars were identified in a search of archival pulsar survey data. These sources, dubbed Rotating RAdio Transients (RRATs), emit detectable radio bursts a few milliseconds in duration, as often as every few minutes to as infrequently as every few hours. The projected Galactic number of RRATs is large, but is not concerning when considering the supernova rate. They seem to be extreme pulsars more easily selected by searches for bright bursts than by traditional Fourier domain searches. I describe a recent archival search which has tripled the number of such radio transient sources in the Parkes Multi-beam Pulsar Survey. I will review what is now known about RRATs, of which there are now 70 published sources. I will describe the pulsar magnetospheric models and highlight their successes, weaknesses and predictions. Finally I will consider how the erratic behaviour of sporadically-emitting neutron stars can be incorporated within these models. An understanding of their radio emission is highly desirable given the expected vast numbers of such sources which will be discovered by current and next generation instruments such as LOFAR, FAST and the SKA.

Observations of Part-Time Pulsars

Author: Neil Young

University of Manchester

Co-Authors:

Session: MAG: Magnetospheres and ionospheres throughout the Universe

Presentation type: Talk

Summary:

Pulsars are extremely magnetised, rapidly rotating neutron stars which produce beams of electromagnetic radiation that sweep across the Earth. They exhibit a variety of interesting phenomena which allow us to gain insight into the physics of the emission process in these extreme magnetic fields. Intermittent pulsars are instrumental in this study due to their meta-stable configurations which result in abrupt cessation or re-activation of their radio emission. Their behaviour is believed to be tied to transient particle flow in the radio emission region. PSR B0823+26 is one such pulsar and has been observed intensively at Jodrell Bank. This pulsar has been found to exhibit seemingly random radio emission phases, over timescales shorter than that observed in the canonical intermittent pulsar PSR B1931+24. In the case of PSR B1931+24, the long-term modulation in the radio emission has been linked with the spin-down rate of the pulsar. Thus, offering a unique opportunity to study how magnetospheric changes can affect the magnetic braking of pulsars. Results from the analysis of the radio emission behaviour of PSR B0823+26 are presented, along with an update of the work carried out on observations of PSR B1931+24.

The Auroral Effects of Thermospheric Dynamics at Saturn

Author: Nicholas Achilleos

UCL

Co-Authors: C. G. A. Smith (UCL Visiting Fellow)

Session: MAG: Magnetospheres and ionospheres throughout the Universe

Presentation type: Talk

Summary:

Observations of Saturn's auroral oval show that it exhibits dramatic changes in morphology during episodes of strong magnetospheric compression which likely trigger magnetic reconnection in the magnetotail region. We present preliminary models of the response of the planet's thermosphere to the expected change in magnetospheric flows, and show that the finite response time (due to the enormous thermospheric inertia) leads to highly structured auroral emissions in the form of 'multiple arcs', qualitatively in agreement with observations. We also discuss the implications for interpreting azimuthal field signatures from spacecraft data, and suggest that so-called 'leading fields' can arise either from truly super-corotating magnetospheric plasma, or from a configuration where this plasma rotates more rapidly than the thermosphere, but where both of these components can still sub-corotate relative to the deep planetary interior.

Saturn's thermosphere as a driver for planetary period phenomena in the magnetosphere

Author: Chris Smith

The Brooksbank School

Co-Authors:

Session: MAG: Magnetospheres and ionospheres throughout the Universe

Presentation type: Talk

Summary:

The well known planetary period phenomena in Saturn's magnetosphere are potentially explained by axial asymmetries in the thermosphere. An atmospheric source for the phenomena offers a natural explanation for both the north-south asymmetry and the seasonal variability of the radio emission period. Since the thermosphere is the region of the neutral atmosphere that is directly coupled to the magnetosphere via the ionosphere, it is a prime candidate for the location of the driving asymmetry. Alternatively, if the driving asymmetry is located deeper in the neutral atmosphere, the thermosphere must mediate the interaction with the magnetosphere. We explore these possibilities using numerical modelling. First, we show that an externally imposed asymmetry in the thermosphere can drive currents into the magnetosphere that produce the observed pattern of perturbation fields in the equatorial magnetosphere. Second, we demonstrate the physical plausibility of a self-sustaining asymmetric wind system in Saturn's thermosphere, associated with positive feedback between ion convection by neutral winds and heating by particle precipitation.

Dual periodicities in â€˜planetary periodâ€™ magnetic field oscillations in Saturnâ€™s tail

Author: Gabrielle Provan

University of Leicester

Co-Authors: D. J. Andrews1, A. J. Coates2, S. W. H. Cowley1, G. Cox1, M. K. Dougherty3, and C. M. Jackman4 1 Department of Physics & Astronomy, University of Leicester, Leicester LE1 7RH, UK. 2Mullard Space Science Laboratory, University College London, Dorking, UK. 3 Blackett Laboratory, Imperial College London, London SW7 2BZ, UK. 4Department of Physics and Astronomy, University College London, 21 London, Gower Place, WC1E 6BT, UK.

Session: MAG: Magnetospheres and ionospheres throughout the Universe

Presentation type: Talk

Summary:

We examine planetary period oscillations in Saturnâ€™s plasma sheet from seven orbital revolutions (Rev) in 2006, when Cassini performed a sequence of deep-tail orbits, passing through the plasma sheet region to maximum distances of ~50 Rs and beyond, for several days on each Rev. The earliest Revs are located near the planetâ€™s equatorial plane, whilst on the later Revs Cassini passes out of the equatorial plane and into the northern hemisphere. In the equatorial region Cassini is still located on southern hemisphere magnetic field lines due to the south-to-north flow of the solar wind during the interval studied [Cowley et al., 2006, Arridge et al., 2008]. The modelled height of the current sheet above the rotational equator has been defined by Arridge et al. [2008]. We use empirical observations to suggest a criterion whereby, during this interval, the magnetospheric oscillations are predominantly at the period of the northern hemisphere Saturn Kilometric Radiaion (SKR) at heights greater than 2.5 Rs above the modelled current sheet, below this the oscillations are predominantly at the period of the southern hemisphere SKR. We further find that the flapping of the current sheet can be organized by the phase of the magnetospheric oscillations.

Periodic motion of Saturnâ€™s nightside plasma sheet

Author: Chris Arridge

MSSL, University College London

Co-Authors: N. AndrÃ© (CESR); K.K. Khurana (UCLA); C.T. Russell (UCLA); S.W.H. Cowley (U. Leicester); G. Provan (U. Leicester); D.J. Andrews (U. Leicester); C.M. Jackman (UCL); A.J. Coates (MSSL UCL); E.C. Sittler (NASA GSFC); M.K. Dougherty (Imperial); D.T. Young (SwRI)

Session: MAG: Magnetospheres and ionospheres throughout the Universe

Presentation type: Talk

Summary:

Saturnâ€™s magnetosphere is replete with magnetospheric periodicities; magnetic fields, plasma parameters, energetic particle fluxes, and radio emissions have all been observed to vary at a period close to that of Saturnâ€™s assumed sidereal rotation rate. In particular, plasma, energetic particles and magnetic fields in Saturnâ€™s magnetotail can be interpreted in terms of periodic vertical motion of Saturnâ€™s outer magnetospheric plasma sheet. The phase relationships between periodicities in different measurable quantities are a key piece of information in validating the various published models which attempt to relate periodicities in different quantities at different locations. It is important to empirically extract these phase relationships from the data in order to distinguish between these models, and to provide further data on which to base new conceptual models. In this paper a simple structural model of the flapping of Saturnâ€™s plasma sheet is developed and fitted to plasma densities in the outer magnetosphere, measured by the Cassini electron spectrometer (CAPS/ELS). We use this model to establish the phase relationships between magnetic field periodicities in the inner and middle magnetosphere and the flapping of the plasma sheet.

Exoplanet Magnetic Fields and Bow Shocks

Author: Aline Vidotto

University of St Andrews

Co-Authors: Moira Jardine, Christiane Helling

Session: MAG: Magnetospheres and ionospheres throughout the Universe

Presentation type: Talk

Summary:

In this talk, I will discuss the presence of bow shocks surrounding the magnetospheres of exoplanets. Bow shocks are formed as a result of the interaction of the planet with the coronal material of the host star, similar to the one formed around the Earth's magnetosphere. Recently, near-UV transit observations of the gas giant planet WASP-12b detected the presence of an extended material ahead of the planetary orbit. We suggest that this material is a bow shock surrounding WASP-12b's magnetosphere and that observable shocks should be a common feature in other transiting systems. According to our model, shock detection through transit observations can constrain the planetary magnetic field Bp. In the case of WASP-12b, this material extends out to 4.2 planetary radii (the size of the planetary magnetosphere), implying an upper limit of Bp<24G. However, for other transiting systems, near-UV observations are still unavailable. If those planets have magnetic fields with intensities similar to Jupiter's (~14G) and orbit stars whose magnetic fields are between 1 and 100G, we estimate that the size of the planet's magnetosphere should range from 1 to 40 planetary radii.

M-I coupling at Jupiter-like exoplanets: implications for detectability of auroral radio emissions

Author: Jonathan Nichols

University of Leicester

Co-Authors:

Session: MAG: Magnetospheres and ionospheres throughout the Universe

Presentation type: Talk

Summary:

We provide the first consideration of magnetosphere-ionosphere coupling at Jupiter-like exoplanets with internal plasma sources such as volcanic moons. We estimate the radio power emitted by such systems under the condition of near-rigid corotation throughout the closed magnetosphere. We thus estimate for different stellar X-ray-UV (XUV) luminosity cases the orbital distances within which the ionospheric Pedersen conductance would be high enough to maintain near-rigid corotation, and we then consider the magnitudes of the magnetosphere-ionosphere currents flowing within the systems, and the resulting radio powers, at such distances. In all XUV luminosity cases studied, a significant number of parameter combinations within an order of magnitude of the jovian values are capable of producing emissions observable beyond 1 pc, in most cases requiring exoplanets orbiting at distances between âˆ¼1 and 50 AU, and for the higher XUV luminosity cases these observable distances can reach beyond âˆ¼50 pc for massive, rapidly rotating planets. The implication is that the best candidates for detection of such internally-generated radio emissions are rapidly rotating Jupiter-like exoplanets orbiting stars with high XUV luminosity at orbital distances beyond âˆ¼1 AU, and searching for such emissions may offer a new method of detection of more distant-orbiting exoplanets.

Magnetic fields in Large Diameter HII regions revealed by Faraday Rotation

Author: Lisa Harvey-Smith

CSIRO Astronomy & Space Science

Co-Authors: G.J. Madsen, B.M. Gaensler (The University of Sydney)

Session: MAG: Magnetospheres and ionospheres throughout the Universe

Presentation type: Talk

Summary:

I will present the results of a study of the line-of-sight magnetic fields in 5 large-diameter Galactic HII regions (Harvey-Smith et al. 2011, in press). Using the Faraday rotation of background polarized radio sources, as well as dust-corrected H-alpha surface brightness as a probe of electron density, we estimated the strength and orientation of the magnetic field along 93 individual sight-lines through the HII regions. Each of the HII regions displayed a coherent magnetic field. The magnetic field strength (line-of-sight component) in the regions ranges from 2 to 7 microgauss, which is similar to the typical magnetic field strength in the diffuse interstellar medium. The slope of magnetic field vs. density in the low-density regime (0.8 < ne < 30 cm-3) is very slightly above zero. We also calculated the ratio of thermal to magnetic pressure, or plasma beta, for each data point, which fell in the range 1 to 25. Finally, we used our results to identify a net direction for the magnetic field along the galactic plane in the solar neighborhood, but we found no evidence for a preferred vertical direction of the magnetic field above or below the Galactic plane.

Surface charging of Saturn's moon Rhea

Author: Geraint H. Jones

MSSL, University College London

Co-Authors: E. Roussos (Max Planck Institut fuer Sonnensystemforschung, Katlenburg-Lindau, Germany); A. J. Coates (MSSL, University College London); F. J. Crary (Southwest Research Institute, San Antonio, Texas, USA)

Session: MAG: Magnetospheres and ionospheres throughout the Universe

Presentation type: Talk

Summary:

Saturnâ€™s second-largest moon, Rhea, resides within the planetâ€™s magnetosphere, and is continuously exposed to the magnetospheric plasma population. We report on Cassini Plasma Spectrometer (CAPS) observations made during the Cassini spacecraft's close encounters with Rhea on March 2, 2010, and January 11, 2011; these demonstrate the fascinating physical processes that occur near solid body surfaces. During the flybys, Cassini passed a few tens of kilometres of the north and south polar regions of the satellite, respectively. The CAPS Electron Spectrometer, ELS, had good pitch angle coverage during the encounters, with its 8 anodes covering directions from towards, to away from the moon. CAPS-ELS observed the expected decrease in the high energy electron population caused by their absorption by Rhea, but also observed an enhancement in the population of electrons at energies below a few hundred eV. We present our interpretation of this population as being associated with the surface charging of Rhea. At the time of both encounters, the moonâ€™s surface was negatively charged, meaning it could reflect certain incoming electrons before they struck the ground, and could also accelerate low energy electrons liberated near the surface. Implications of the observations are discussed.

Solar wind - magnetosphere - ionosphere coupling at the Earth

University of Leicester

Co-Authors: S.E. Milan (University of Leicester)

Session: MAG: Magnetospheres and ionospheres throughout the Universe

Presentation type: Talk

Summary:

Unlike magnetosphere-ionosphere (MI) coupling at the gas giants, where it is governed largely by planetary rotation, MI coupling at the Earth is dominated by solar wind-magnetosphere coupling at the magnetopause. This coupling is facilitated primarily through reconnection between the terrestrial and interplanetary magnetic fields, with the nature of the resultant magnetosphere-ionosphere dynamics being determined by changes in the strength and orientation of the latter. In the dayside ionosphere the effects of this dynamic coupling are readily apparent, the ionospheric plasma responding almost instantaneously to the direct driving by the solar wind. In the nightside ionosphere, on the other hand, the electrodynamics are complicated by internal magnetospheric processes that result from the storage and release of solar wind energy in the magnetotail and couple to the ionosphere in different ways. In this paper we discuss the solar wind-magnetosphere-ionosphere interaction, focussing on these dynamic magnetotail processes and their highly variable ionospheric counterparts.

Ionosphere-magnetosphere waves

Author: Alexander J. B. Russell

University of Glasgow

Co-Authors: A. N. Wright (University of St Andrews)

Session: MAG: Magnetospheres and ionospheres throughout the Universe

Presentation type: Talk

Summary:

Ionospheres and magnetospheres are each fascinating in their own right but their combination produces intriguing surprises. Among the most fundamental are newly-discovered ionosphere-magnetosphere' waves, produced by two-way feedback between ionospheric plasma density and field-aligned currents in the magnetosphere. I will demonstrate the properties of these waves, give a few simple formulas that describe them and show their powerful ability to produce small-scales from large-scales.

Cassini observations of plasmoid structure and dynamics

Author: Caitriona Jackman

University College London

Co-Authors: J.A. Slavin (NASA Goddard); S.W.H. Cowley (Univ. of Leicester)

Session: MAG: Magnetospheres and ionospheres throughout the Universe

Presentation type: Talk

Summary:

Cassini observations of plasmoid structure and dynamics: Implications for the role of magnetic reconnection in magnetospheric circulation at Saturn. On examination of data from the Cassini magnetometer instrument during the deep tail orbits in 2006, 34 direct encounters with plasmoids were found. We show a case study example of three such plasmoids over three hours, and derive a reconnection rate over this interval of 350 kV. We present the theoretical field signatures which would arise from magnetotail reconnection on open and closed field lines. We show the results of a superposed epoch analysis of all 34 plasmoids and find that on average, plasmoids at Saturn are followed by extended observation of the post-plasmoid plasma sheet, and for each event, up to 2 GWb of flux on average can be closed through reconnection of lobe field lines. Assuming a Dungey-cycle timescale of ~6-10 days at Saturn, our calculations predict an average plasmoid recurrence rate of ~2-3 per day. However, these observations are not expected to be spread evenly, but rather clustered together as the magnetosphere is driven intermittently by the Dungey cycle.

Coupling of Dungey and Vasyliunas cycle reconnection: Drivers and observable consequences

Author: Chris Arridge

MSSL, University College London

Co-Authors: A.P. Walsh (MSSL UCL)

Session: MAG: Magnetospheres and ionospheres throughout the Universe

Presentation type: Poster

Summary:

System-level models of reconnection cycles in rapidly rotating magnetospheres typically consider the Dungey and Vasyliu Ì„nas cycles in isolation and make specific predictions about the ion composition changes associated with these processes. However, in order to form and release a plasmoid as part of the Dungey cycle, reconnection must occur on closed field lines before any open flux is reconnected. This naturally leads to a coupling of these two cycles. In this presentation we conceptually explore the observable consequences of this coupling in terms of time-dependence in the ion composition of reconnection flows as reconnection proceeds through the closed and then open magnetic flux. We argue that in the absence of any solar wind driving the Vasyliu Ì„nas cycle can in principle proceed in isolation, but the same is not true of the Dungey cycle as long as there is significant mass- loading in a rapidly rotating magnetosphere. We also explore the driving of these cycles using quantitative models of the magnetotail which include the effects of the centrifugal force. The onset of reconnection in the magnetotail depends on a thinning of the current sheet that might arise due to i) stretching of field lines due to the centrifugal force, ii) compression of the plasma sheet by the addition of open flux to the lobes or the passage of a solar wind compression, or iii) a combination of these effects. We consider the stability of the magnetotail to examine whether triggering of tail reconnection due to solar wind compression requires a particular mass content of the magnetotail.

The Magnetosphere of Uranus

Author: Chris Arridge

MSSL, University College London

Co-Authors: N. AndrÃ© (CESR); A. Masters (MSSL UCL); The Uranus Pathfinder Consortium

Session: MAG: Magnetospheres and ionospheres throughout the Universe

Presentation type: Poster

Summary:

The configuration of all the planetary magnetospheres in the solar system is determined by the relative orientations of the planetâ€™s spin axis, its magnetic dipole axis, and the solar wind flow. In the general case, the angle between the magnetic dipole axis and the solar wind flow is a time-dependent quantity and varies on both diurnal and seasonal timescales. Uranus presents a particularly interesting and poorly understood case because this angle not only varies seasonally but because of Uranusâ€™ large obliquity the extent of diurnal oscillation varies with season. At solstice this angle does not vary with time and Uranusâ€™ magnetic dipole simply rotates around the solar wind flow vector. This is a magnetospheric configuration not found anywhere else in the solar system. This unique arrangement may lead to a rapidly reconfiguring system which changes from an open to closed configuration over a uranian day and which may have a closed flow region which does not impede solar-wind driven convection. Uranus thus presents a very different system and represents a challenge for our theories of how magnetospheres work. In this talk we review our understanding of the uranian magnetosphere and discuss future exploration and study of this system.

The SPARK Mission to understand particle acceleration extremes

Author: David Williams

UCL Mullard Space Science Lab

Co-Authors: S.A. Matthews (UCL), K.L. Klein (Obs. de Paris), E. Kontar (U. Glasgow), D. Smith (UC Santa Cruz), S. Krucker (UC Berkeley), A. Lagg (MPS), G. Hurford (UC Berkeley), N. Vilmer (Obs. de Paris), A. MacKinnon (U. Glasgow), V. Zharkova (U. Bradford), L.Fletcher (U. Glasgow), I. Hannah (U. Glasgow), P. Browning (U. Manchester), D. Innes (MPS), G. Trottet (Obs. de Paris), C. Foullon (U. Warwick), V. Nakariakov (U. Warwick), L. Green (UCL), M. Mathioudakis (QUB), O. Limousin (CEA France), E. Verwichte (U. Warwick), S. Dalla (UCLAN), T.Neukirch (U. St Andrews), H. Aurass (AI Potsdam), G. Mann (AI Potsdam)

Session: MIS: Solar Missions Forum

Presentation type: Talk

Summary:

Energetic particles fill the universe and can tell us how that universe originated and what it is made of. They shape the way in which our own and other solar systems work, how planets are formed and what the conditions for the emergence and continuation of life might be. The process of particle acceleration itself is found throughout the universe in environments as diverse as stellar coronae, active galactic nuclei, the coronae of accretion disks around black holes, the magnetospheres of neutron stars and planetary atmospheres interacting with the wind of their star. Despite the critical role of particle acceleration in shaping the universe as we know it, the details of the physical processes themselves poorly understood. The SPARK mission will primarily observe the Sun in order to understand the processes of particle acceleration involved and in particular its extremes. SPARK will make the first space measurements of the far infrared component of solar flares, the first series of gamma-ray line images, and the most sensitive measurements yet of the hard X-ray (HXR) and gamma-ray spectrum, placing us ideally to make significant progress in understanding the roles of electric fields, shocks and wave-particle interactions in accelerating particles on the Sun.

Alfven-MICE: How does the aurora work

Author: Colin Forsyth

UCL MSSL

Co-Authors: A.N.Fazakerley (UCL MSSL, UK); M.Berthomier (LPP, France); Alfven-MICE Team

Session: MIS: Solar Missions Forum

Presentation type: Talk

Summary:

The aurorae are a dynamic feature of coupled magnetosphere-ionosphere systems that represent the deposition of energy from the magnetosphere into the ionosphere. The processes by which electrons are accelerated to sufficient energies to excite auroral emission in the atmosphere represents a breakdown in magnetohydrodynamics (MHD) and a violation of the first adiabatic invariant. Despite many decades of studying these processes, the fundamental physics of the acceleration processes is not well understood, due in part to the fact that the accelerating structures are distributed along the magnetic field and thus cannot be resolved by single spacecraft observations. Alfven-MICE is a dual spacecraft mission that will address the unanswered questions about the acceleration processes above the aurora such as â€œwhat is the structure of the acceleration regionâ€; â€œhow do large, localized parallel electric fields form and evolveâ€; â€œhow efficient are the different ionospheric outflow mechanismsâ€. In this presentation, we outline the principal goals of the Alfven-MICE mission, the mission design and strategy required to answer these questions.

Uranus Pathfinder: Exploring the Origins and Evolution of Ice Giant Planets

Author: Chris Arridge

MSSL, University College London

Co-Authors: Craig B. Agnor (QMUL); Nicolas AndrÃ© (CESR); Kevin H. Baines (NASA JPL); Leigh N. Fletcher (U. Oxford); Daniel Gautier (LESIA); Mark Hofstadter (NASA JPL); Geraint H. Jones (MSSL UCL); Laurent Lamy (LESIA); Yves Langevin (IAS/CNRS); Olivier Mousis (Obs. de BesanÃ§on); Nadine Nettelmann (U. Rostock); Christopher T. Russell (UCLA); Tom Stallard (U. Leicester); Matthew S. Tiscareno (Cornell); Gabriel Tobie (LPG/CNRS); Uranus Pathfinder Consortium

Session: MIS: Solar Missions Forum

Presentation type: Talk

Summary:

Ice Giants (Uranus and Neptune) are different from Gas Giants (Jupiter and Saturn) in a number of essential ways and yet our exploration of the Ice Giants in our own Solar System remains incomplete, with a number of fundamental questions unanswered. Uranus Pathfinder (UP) is a mission concept proposed to ESA in response to its 2010 call for medium-class missions. UP proposes to explore the fundamental processes at work in the planet itself (its interior and atmosphere) and in its planetary environment (magnetosphere, satellites, and rings). The mission will provide observations and measurements that are vital for understanding the origin and evolution of Uranus as an Ice Giant planet, providing a missing link between our Solar System and planets around other stars. UP thus represents the quintessential aspects of ESAâ€™s Cosmic Vision. The mission architecture for UP involves a Rosetta-class spacecraft launching in 2021 on a Soyuz-Fregat launch vehicle, a 15 year transfer (incorporating numerous gravity assists) to Uranus, and insertion into an eccentric polar orbit. UP has significant community support with 164 scientists worldwide (108 in Europe) lending their support to the mission. In this talk we describe the science case, mission concept, and scientific payload for Uranus Pathfinder.

The down selection of ESA (followed by discussion)

Author: Mark Lester

University of Leicester

Co-Authors:

Session: MIS: Solar Missions Forum

Presentation type: Talk

Summary:

The down selection of the mission proposals submitted to the call by ESA for its M3 mission was undertaken earlier in 2011. This short presentation will provide an overview of the review structure and the process by which the down selection occurred. The review will concentrate on the process as run by the Solar System and Exploration Working Group.

CINEMA/TRIO: A three-spacecraft space weather CubeSat mission

Author: Tim Horbury

Imperial College London

Co-Authors: P. Brown, J. P. Eastwood, M. Archer (Imperial College London), R. P. Lin, T. Immel, D. Glaser (Space Science Lab, UC Berkeley), D.-H. Lee, J. Seon, H. Jin (School of Space Research, Kyung Hee University, Yongin, Republic of Korea)

Session: MIS: Solar Missions Forum

Presentation type: Talk

Summary:

CINEMA/TRIO (CubeSat for Ions, Neutrals, Electrons and Magnetic fields) is a mission of three identical CubeSats in high inclination low Earth orbits, carrying two instruments: a suprathermal electron, ion and neutral sensor (STEIN) and a magnetometer from Imperial College (MAGIC). The spacecraft will provide multi-point measurements of near â€“Earth space including: stereoscopic energetic neutral atom imaging of the ring current with 1keV energy resolution; direct measurement of ion precipitation in the auroral regions including pitch angle distributions, from just a few keV; full energy characterisation of electron microbursts; and high cadence measurements of magnetospheric waves and transients. The multi-point magnetic field measurements of CINEMA/TRIO will be an ideal test bed for space weather effects on data from ESAâ€™s upcoming SWARM mission. The mission is a collaboration of UC Berkeley, Kyung Hee University and Imperial College London and has received funding from the US National Science Foundation and Koreaâ€™s World Class University programme; the first spacecraft is expected to launch in early 2012.

Solar Orbiter

Author: Tim Horbury

Imperial College London

Co-Authors: C. Owen (MSSL/UCL), L. Harra (MSSL/UCL), A. Fludra (RAL/STFC)

Session: MIS: Solar Missions Forum

Presentation type: Talk

Summary:

Solar Orbiter is a candidate for ESAâ€™s next medium-class mission. Planned for launch in 2017 and flying closer to the Sun than Mercury, Solar Orbiter will carry a comprehensive complement of remote sensing and in situ instrumentation. By observing coronal holes, active regions and transient events and then directly measuring the resulting outflowing plasma, fields and energetic particles from a sufficiently close distance that propagation effects are minimised, Solar Orbiter will provide vital new information on how the Sun connects into space and influences the Solar System at large, including effects on the terrestrial system. In the later stages of the mission the orbit will be inclined, enabling Solar Orbiter to make the first detailed observations of the Sunâ€™s polar regions, including helioseismic and magnetic field measurements of the high latitude manifestations of the Sunâ€™s dynamo. Four of the spacecraftâ€™s ten instruments have UK involvement, placing the UK in a central role in the mission and providing a unique opportunity for the UK solar, heliospheric and plasma communities. We present the overall mission goals and provide an update on the current status of the mission, spacecraft and instruments.

LEMUR: the Large European Module for solar Ultraviolet Research

Author: Lucie Green

MSSL - UCL

Co-Authors:

Session: MIS: Solar Missions Forum

Presentation type: Talk

Summary:

LEMUR, the Large European Module for solar Ultraviolet Research, is a proposal for a VUV telescope for imaging spectroscopy of the solar atmosphere. The LEMUR proposal was submitted to the recent ESA call for M-class missions and, if funded, would fly on the Japanese Solar-C spacecraft (plan-B option, launch date ~2019) as one of a suite of three telescopes. The other two telescopes being a UV-visible-near-IR telescope for imaging and spectropolarimetry (the largest solar telescope to fly in space by a factor of 9 in collecting area) and a next-generation high-resolution X-ray telescope. In this talk I will review the instrument concept and the scientific objectives of LEMUR and Solar-C. Simultaneous spectroscopic measurements sampling all temperature ranges of the solar atmosphere are essential to achieving the science goals of the Solar-C mission and LEMUR is a key component for its success.

The STEREO Mission - Towards operational space weather forecasting

Author: C. J. Davis

RAL Space, STFC Rutherford Appleton Laboratory

Co-Authors: R. A. Harrison (RAL Space), J. A. Davies (RAL Space), S. R. Crothers (RAL Space), C. J. Eyles (RAL Space)

Session: MIS: Solar Missions Forum

Presentation type: Talk

Summary:

The UK-built Heliospheric Imagers onboard the NASA STEREO mission have been providing a unique view of the heliosphere. In the four years since STEREO's launch, techniques have been developed that use data from the HI instruments to estimate the speed and direction of coronal mass ejections (CMEs) and Co-rotating interaction regions (CIRs). In addition to the higher resolution science data, the STEREO spacecraft also return a near real-time data stream that enables genuine predictions of Earth-impacting events from these techniques. Recently, the two STEREO spacecraft reached opposite sides of the Sun and are now drifting even further away from the Earth. While this will eventally make it impossible to track Earth-directed CMEs, data from the Heliospheric Imagers will still provide valuable information about the ambient solar wind that will improve the established space weather prediction models.

Filming the Earth from Space

Author: Chris Rose

University of Sheffield

Co-Authors: A.J.Baker (University of Sheffield)

Session: MIS: Solar Missions Forum

Presentation type: Talk

Summary:

The aim of this project was to film the Earth from near space on a low budget, highlighting the procedure from start to finish, making it accessible and understandable to viewers. A weather balloon was launched from Ashbourne, Derbyshire on 17 December 2010, and was in flight for approximately two hours and fifty minutes, before landing in a field in Strethall, Essex, a journey of just over 100 miles. The helium balloon carried a payload consisting of a parachute (for a safe descent), two cameras and a tracking device. Since the cameras were recording video continuously onto their internal memory, the safe ascent and descent, and tracking of the payload were critical to the success of the mission. Using some basic engineering principles, we were able to ensure the effective launch, and safe return of a near space balloon, which resulted in some stunning images of the curvature of the Earth and the blackness of space.

The UCLan SDO data hub

Author: Silvia Dalla

University of Central Lancashire

Co-Authors: D.S.Brown, S.A.Chapman, M.Marsh, S.Regnier, R.W.Walsh (University of Central Lancashire)

Session: MIS: Solar Missions Forum

Presentation type: Poster

Summary:

A data pipeline for the distribution of SDO data products has been developed throughout a number of countries in the US, Europe and Asia. The UK node within this pipeline is at the University of Central Lancashire (UCLan), where a data center has been established to host a rolling AIA and HMI archive, aimed at supplying SDO data to the large UK solar scientific community. This presentation will describe the hardware and software structures of the archive, with focus on the ways in which scientists can retrieve data. Usage statistics and download speeds for the UCLan hub will also be presented.

The Lloyds report on space weather â€“ lessons for research

Author: Mike Hapgood

RAL Space

Co-Authors:

Session: MIST: MIST General session

Presentation type: Talk

Summary:

Lloyds 360 Risk Insight and RAL Space recently developed a report about space weather impacts on business. This talk will describe the vital role that scientific understanding plays in the report and explore how that understanding may be expanded. It will emphasise that space weather is about natural environments (in space, in the atmosphere and on the ground) that can disrupt advanced technologies. Thus we must understand the features of those environments that cause that disruption - and the physical phenomena that drive those features: some on the Sun, some in interplanetary space and some in the terrestrial environment. It is also vital to understand how the environment interacts with advanced technologies - so that we identify and study features that can provide useful information to the engineering communities that build and operate those technologies. This will most often take the form of environmental specifications that can be used to design resilient technologies, but in many cases will also include the need to provide alerts on space weather events. Finally the talk will look beyond current knowledge and suggest areas in which future research can improve our ability to understand and mitigate space weather risks.

THEMIS observations of magnetic holes associated with dipolarizations

Author: Michael Balikhin

University of sheffield

Co-Authors:

Session: MIST: MIST General session

Presentation type: Talk

Summary:

The properties of the magnetic depressions that have been observed by THEMIS soon after the registration of the dipolarisation fronts are investigated. These magnetic dispersions were interpreted as mirror structures, similar to the magnetic holes observed in the terrestrial magnetosheath and solar wind. In the present paper, it is shown that observed features of these waves contradict the physics of the mirror mode. The scale of these structures are too small for a correlative study by two or more THEMIS spacecraft to provide reliable identification of the wave mode. However single spacecraft measurements are sufficient to rule out the mirror nature of the observed nonlinear waves.

Substorm and magnetic storm effects on the cross-tail current sheet

Author: Mrs Elizabeth Davey

University of Leicester

Co-Authors: M. Lester; S.E. Milan; R.C. Fear (University of Leicester) all co-authors

Session: MIST: MIST General session

Presentation type: Talk

Summary:

We present a study of the dynamics of the mid-tail region of the current sheet. We have employed data from the Cluster spacecraft from 2001 to 2007. Specifically, we have taken fluctuations of the x component of the magnetic field (Bx) measured by Cluster 3 around Bx=0 to indicate that the current sheet is in motion. The effects of substorm and magnetic storm activity on current sheet motion were investigated using the AE index and SYM-H data. The crossings of the current sheet made by the spacecraft for each orbit were studied statistically, allowing a comparison of orbits and the intrinsic geomagnetic conditions. Results indicate that the current sheet is more dynamic during orbits with greater than average magnetic activity, as evidenced by the AE index, although there is also some evidence of a stabilisation of the current sheet due to an enhanced ring current during magnetic storms.

From Nowcasting to Forecasting; the Importance of Thermospheric Preconditioning of the Ionosphere

Author: Anasuya L. Aruliah

University College London

Co-Authors:

Session: MIST: MIST General session

Presentation type: Talk

Summary:

The polar region environments are a critical measure of global climate change. The polar regions are also important for space weather studies owing to the dipole nature of the Earthâ€™s magnetic field which means that solar wind particles can only enter the Earthâ€™s atmosphere near the magnetic poles. There has recently been a recognition of a link between space weather and tropospheric weather. This makes it important that space weather models are as realistic as possible, which requires that they are firmly constrained by observations, as are climate models. The ionosphere in the polar regions responds almost immediately to forcing by the solar wind, however, its response is modulated by interaction with the neutral atmosphere. Currently space weather studies are focusing on â€œnow-castingâ€ using measurements of the ionosphere. In order to â€œfore-castâ€ it is necessary to monitor the thermosphere which preconditions the response of the ionosphere. However, there are far fewer instruments directly measuring the thermosphere compared with those measuring the ionosphere and magnetic field. Without direct measurements of the thermosphere, studies of the magnetosphere-ionosphere-thermosphere system rely on deriving neutral parameters from measurements of the ionosphere or using models. Several studies using Fabry-Perot Interferometers have already shown that the commonly used MSIS model is inadequate to represent the observed spatial and temporal variations in high latitude regions where the MIT system is the most dynamic. Existing theoretically based models have too poor a spatial resolution to simulate the localised heating and variability seen on scales of a few hundred kilometres. This paper demonstrates the importance of contemporaneous thermospheric observations in any attempt at forecasting space weather.

EISCAT_3D: A European three-dimensional imaging radar for atmospheric and geospace research

Author: Esa Turunen

EISCAT Scientific Association

Co-Authors: EISCAT 3D Project Team

Session: MIST: MIST General session

Presentation type: Talk

Summary:

EISCAT_3D will be Europeâ€™s next-generation radar for the study of the upper atmosphere and geospace. Several large active phased-array antenna transmitter and receiver arrays will be located across three countries in northern Scandinavia, withtens of thousands, up to more than 100 000 individual antenna elements. EISCAT_3D combines key attributes which have never before been available together in a single radar, such as volumetric imaging and tracking, aperture synthesis imaging, multistatic configuration, improved sensitivity and transmitter flexibility. The use of advanced beam-forming technology allows the beam direction to be switched in milliseconds, rather than the minutes which it can take to re-position dish-based radars. This allows very wide spatial coverage to be obtained, by interleaving multiple beam directions to carry out quasi-simultaneous volumetric imaging. EISCAT_3D has a modular configuration, which allows an active array to be split into smaller elements to be used for aperture synthesis imaging. The result will be an entirely new data product, consisting of range-dependent images of small sub-beamwidth scale structures, with sizes down to 20 m. The science case of EISCAT_3D is versatile, ranging from global change related studies of the atmospheric energy budget and coupling of atmospheric regions to space plasma physics with both small-scale structures and large-scale processes, as well as planetary and meteor radar applications. Additional value is in opportunities for continuous geospace environment monitoring and service applications such as space debris detection and mitigation of space weather effects.

A novel EISCAT technique to monitor thermospheric neutral density for climate change

Author: M. J. Kosch

Lancaster University

Co-Authors: Y. Ogawa (National Institute of Polar Research, Japan), M.T. Rietveld (EISCAT Scientific Association, Norway), S. Nozawa (STELab, Nagoya University, Japan) and R. Fujii (STELab, Nagoya University, Japan)

Session: MIST: MIST General session

Presentation type: Talk

Summary:

Ion outflow from the high-latitude ionosphere is a well-known phenomenon and an important source of plasma for the magnetosphere. It is also well known that pumping the ionosphere with high-power high-frequency radio waves causes electron heating. This can be accompanied by artificially-induced ion upwelling. We analyse such a controlled experiment at EISCAT up to 600 km altitude. The pump-enhanced electron temperatures reached up to ~4000 K above 350 km, and ion upwelling reached up to ~300 m/s above 500 km altitude. The electron gas pressure gradient can explain ion upwelling, at least up to 600 km altitude. Such active experiments open the possibility to estimating the F-layer ion-neutral collision frequency and therefore the neutral density with altitude from ground-based observations. For a test case (9/10/1998), we find the neutral thermospheric density to be well below (1.8 â€“ 3.3X) that predicted by the MSIS model, consistent with climate change expectations.

The response of an incoherent scatter radar and riometer to the precipitation of MeV electrons

Author: Andrew J. Kavanagh

Lancaster University

Co-Authors: C. J. Rodger (University of Otago), M. A. Clilverd (British Antarctic Survey), C-F. Enell (Sodankyla Geophysical Observatory) and F. Honary (Lancaster University)

Session: MIST: MIST General session

Presentation type: Talk

Summary:

On 31 July 2009, the Earth passed through a corotating interaction region and entered a weak (<450 km/s) high speed solar wind stream. This coincided with a drop to normal levels of the >2 MeV electron flux at geostationary orbit following several days of enhancement. The EISCAT VHF radar was measuring the lower D-region on the afternoons of the 28th, 30th and 31st July; following the onset of the HSS it recorded a short-lived (~15 minute) enhancement in electron density that peaked close to 60 km altitude. This was simultaneously observed as a discrete patch of radio absorption by the Imaging Riometer for Ionospheric Studies (IRIS) at Kilpisjarvi. We use the observations from EISCAT to estimate the characteristics of the precipitating electrons and employ the Sodankyla Ion Chemistry Model to examine the resultant changes to ion chemistry in the mesosphere. We will consider the response of a riometer to varying levels of MeV precipitation and thus determine their effectiveness in studies of radiation belt loss to the atmosphere.

Lancaster GIC Workshop

Author: Farideh Honary

Lancaster University

Co-Authors: J. Wild (Lancaster University);A.W.P. Thomson (BGS);M. Hapgood (RAL, Lancaster University)

Session: MIST: MIST General session

Presentation type: Talk

Summary:

We will be reporting on the Geomagnetically induced currents (GIC) workshop which will be held at Lancaster University on 30th and 31st March 2011. Experts from USA, Europe and South Africa are attending at this two day workshop to discuss challenges in understanding and predicting Geomagnetic hazard to National Power Grids. Outcome of the workshop's discussions on risks and mitigation will be presented.

Polar satellite Poynting flux/IRIS riometer signals

Author: Peter Tullet

formerly at Lancaster University

Co-Authors:

Session: MIST: MIST General session

Presentation type: Talk

Summary:

Poynting flux time series arising from disturbances in the electric and magnetic field encountered by the Polar satellite have been analysed in relation to ground-based observations utilising the Imaging Riometer for Ionospheric Studies [IRIS] in order to investigate energy transfer by electromagnetic wave propagation from the magnetosphere to the ionosphere. Poynting Flux Impulses detected when the Polar satellite was in the magnetospheric tail region were found to be coincident with observations of enhanced ionospheric cosmic radio background absorption detected by IRIS at KilpisjÃ¤rvii, Finland, even though the Polar satellite was often remote from the KilpisjÃ¤rvii magnetic field-line at the times of these events.

Combined long term temperature study with EISCAT and Fabry Perot Interferometers

Author: H.C. Iris Yiu

University College London

Co-Authors: Anasuya Aruliah, Eoghan Griffin, Ian McWhirter (UCL)

Session: MIST: MIST General session

Presentation type: Poster

Summary:

There is renewed interest in the monitoring of upper atmospheric temperatures because of the recent extended solar minimum cycle 23/24, as well as the study of the long-term temperature trend in the upper atmosphere due to the increase in green-house gases. Incoherent Scatter radars like EISCAT can be used to provide long-term ion temperatures, which can act as a proxy to the neutral thermospheric temperatures when geomagnetic activity is low. However, this is an indirect measure. The UCL Svalbard Fabry Perot Interferometer (FPI) has been measuring the red line 630.0nm emissions in the high latitude regions for nearly 25 years, and is able to provide direct measurements of the neutral temperature with appropriate calibration. A study of ten years (1999-2009) of FPI neutral temperatures is presented here, with comparisons to the ion temperature measurements from the EISCAT ESR, and semi-empirical model results from MSIS. The potential and importance of a future longer-term combined radar-FPI temperature study is discussed.

Simulation of spacecraft surface charging near dusty lunar atmosphere

Author: Farideh Honary

Lancaster University

Co-Authors: A.K. Anuar (Lancaster University), M. Hapgood (CLRC, Lancaster University), J-F. Roussel (Onera)

Session: MIST: MIST General session

Presentation type: Poster

Summary:

A charging simulation by charged dust streaming from lunar surface on spacecraft is presented in this paper. These charged dust is caused by the charging of lunar surface by the solar wind and can be lifted up to 100km when accelerated by the lunar surface's electric field. SPIS software which originally intended to study spacecraft-plasma interaction is extended in order to include dust with varying charge and mass, and Monte Carlo collision algorithm is introduced to simulate the dust-plasma interaction using particle in cell method. The dust charge number depends on the radius and mass, which determine the amount of lift each individual dust experience at certain lunar surface potential. The simulation is set up for near the terminator region of the moon, where streaming dust has been reported, and the spacecraft is modeled as a simple spherical probe made from conducting coating.

Constraining radar interferometer design based on optical aurora images

Author: Sam Tuttle

Southampton University

Co-Authors: BjÃ¶rn Gustavsson (Southampton University), Betty Lanchester (Southampton University)

Session: MIST: MIST General session

Presentation type: Poster

Summary:

The range of spatial frequencies required to undertake interferometric incoherent scatter radar studies of the aurora is presented. The range of frequencies constrains the baseline pattern and hence antenna configuration of the required interferometer. High spatial resolution optical images of the aurora, obtained using the Auroral Structure and Kinetics (ASK) instrument, were used to determine the characteristic spatial frequencies using a Fourier analysis.

A solar wind-magnetosphere coupling function deduced by the NARMAX OLS-ERR algorithm

Author: Richard Boynton

University of Sheffield

Co-Authors: M. A. Balikhin (University of Sheffield); S. A. Billings (University of Sheffield)

Session: MIST: MIST General session

Presentation type: Poster

Summary:

A NARMAX nonlinear system identification technique was used to obtain a solar wind-magnetosphere coupling function. The NARMAX OLS-ERR algorithm is able to determine the causal relationship between input and output for nonlinear systems. The algorithm used solar wind data as the input and the Dst index as the output, which was then able to rank different combinations of the solar wind parameter in order of their predictive capabilities. These obtained coupling functions were compared to those suggested in previous analytical and data based studies. The most appropriate coupling function that the algorithm found was n^(1/2)V^(alpha)B_T sin^6(theta/2), where the power of velocity, alpha, should be in the range 2 - 3.

Venus Express: Its contribution to plasma science

Author: Simon Walker

University of Sheffield

Co-Authors: M. A. Balikhin (University of Sheffield); S. A. Pope (University of Sheffield); T. L. Zhang (Austrian Academy of Sciences, Graz)

Session: MIST: MIST General session

Presentation type: Poster

Summary:

The Venus Express spacecraft (VEX) has a very limited plasma package consisting of a particle instrument (ASPERA) and a magnetometer (MAG). VEX is also a magnetically unclean spacecraft. However, in spite of such a limited plasma payload VEX has not only advanced our understanding of Venus-Solar wind interactions but also contribted to fundamental problems of space plasma. Examples of such observations include a new class of collisionless shock that exhibits kinematic relaxation, observations of giant vortices in the magnetosheath that appear to be generated by as a result of the Kelvin-Helmholtz instability at the ionopause, and the probable origin and dynamics of mirror waves. These and other findings of VEX MAG are reviewed.

Non-Axisymmetry Magnetic Field in the Turbulence Solar Wind at Inertial and Kinetic Scales

Author: Andrew Turner

CFSA, University of Warwick

Co-Authors: S. C. Chapman (CFSA, University of Warwick) G. Gogoberidze (CFSA, University of Warwick) B. Hnat (CFSA, University of Warwick)

Session: MIST: MIST General session

Presentation type: Poster

Summary:

The Solar wind presents a natural example of a high Reynolds, near-collisionless plasma with a well defined power law range for the power spectral density of magnetic field fluctuations observed in-situ, suggestive of an Inertial range of Magnetohydrodynamic turbulence that spans many decades in the time domain. Scaling in magnetic field fluctuations is also observed on temporal scales between the ion and electron gryoperiod, suggesting a kinetic range of turbulence. The kinetic range fluctuations are distinct in character from those of MHD scales, showing non-Gaussian monoscaling behaviour, unlike the MHD inertial range which shows intermittent multiscaling behaviour consistent with fluid turbulence. A recent, unexpected observation is the fluctuations in the magnetic field become progressively less axisymmetric about the local magnetic field as we look on kinetic scales. We perform statistical analysis on Cluster FGM (67Hz) and STAFF (450 Hz) experiment, Stereo FGM (8 Hz) and ACE FGM (0.017 Hz) data in fast solar wind. Power Spectral Density shows a distinct power asymmetry in the two perpendicular directions ordered with respect to the local magnetic field and the solar wind flow direction. We also perform a Minimum Variance Euler Angle Decomposition. The results will be discussed. We acknowledge the ACE, Stereo and Cluster data teams and funding supplied by STFC.

Examining the evolution of transient solar wind structures using STEREO/HI

Author: Anthony Williams

University of Leicester

Co-Authors: S.E.Milan (University of Leicester); J.A. Davies (Rutherford Appleton Laboratory)

Session: MIST: MIST General session

Presentation type: Poster

Summary:

The Heliospheric Imagers (HI) on the STEREO spacecraft allow for continuous coverage of transient CMEs in the solar wind as they travel through the inner heliosphere. The HI images produced show light which has been Thomson scattered by free electrons in the solar wind plasma. By taking a cross-section along the ecliptic of these images we examine the relative intensity of the scattered light as a function of radial distance and using multiple such cross-sections we study the evolution of transients with time. In this study we report multiple Earth directed transients and use in-situ data from the ACE spacecraft to gain a further understanding of how different transients evolve during their passage towards the Earth.

The variation of F-region radio electron heating with pump power

Author: Andrew Senior

Dept. of Physics, Lancaster University

Co-Authors: M. J. Kosch (Dept. of Physics, Lancaster University)

Session: MIST: MIST General session

Presentation type: Poster

Summary:

The power deposited into the ionospheric electrons by a high-power HF radio wave can be determined by inverting the electron temperature profiles measured by incoherent scatter radar. In this study, an experiment using the EISCAT HF facility and UHF radar are used to investigate how the electron heating varies with the power of the pump radio wave. It is found that the heating is approximately proportional to the pump power, i.e. the efficiency of the heating mechanism is approximately constant with power. The consequences of pump wave absorption in the D-region for heating of the F-region are also investigated.

Sun et LumiÃ¨re: Auroral and ionospheric evolution during substorms and ramifications for the Earthâ€™s

Author: Steve Milan

University of Leicester

Co-Authors: S. E. Milan (1), A. Grocott (1), G. Provan (1), J. S. Gosling (1), S. M. Imber (2), and B. Hubert (3) (1) University of Leicester, UK (2) Goddard Space Flight Center, USA (3) University of Liege, Belgium

Session: MIST: MIST General session

Presentation type: Poster

Summary:

We describe the general characteristics of the evolution of the auroral, ionospheric, and magnetotail signatures of magnetospheric substorms. We present results of superposed epoch analyses of 2000 substorms, identified by Frey et al. (2004), of Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) auroral images, Super Dual Auroral Radar Network (SuperDARN) ionospheric flows, and other measures of magnetospheric disturbance. In particular, we examine the effect of the onset latitude on the subsequent evolution of the substorms, the dependence of the onset latitude on the intensity of the ring current, and the solar wind conditions that lead to magnetospheric storm onset. The results are interpreted within the expanding/contracting polar cap paradigm (ECPC), and the ramifications for magnetotail structure and dynamics are discussed.

UCL and Japan FPIs â€“EISCAT UHF radars tri-static experiment

Author: H.C. Iris Yiu

University College London

Co-Authors: Anasuya Aruliah (UCL), Mike Kosch (Lancaster,STELab), Nozawa Satonori (STELab), Shin-ichiro Oyama (STELab), Kazuo Shiokawa (STELab),Ian McWhirter (UCL), V.S.C.Howells (RAL)

Session: MIST: MIST General session

Presentation type: Poster

Summary:

The results of one of the last tristatic ion-neutral coupling experiments using the EISCAT mainland tristatic radar configuration, with three co-located Fabry-Perot interferometers (FPIs), are presented here. The results show the importance of three-dimensional measurements when studying small-scale structures in the high latitude thermosphere, and the possible applications to the future EISCAT 3D project. The FPIs involved are two UCL FPIs at Kiruna and SodankylÃ¤, as well as a Japanese STELab FPI in TromsÃ¸. Though only bistatic neutral measurements from the FPIs were available due to cloudy sky conditions, we present one of the interesting case studies when an auroral arc appeared under an extremely quiet period in the extended solar minimum in 11th February 2010. Together with the tristatic EISCAT radar results, the FPIs provide a detailed study of the dynamics and energetics of small-scale ion-neutral interactions.

UK Solar System Data Centre - life with NERC and STFC

Author: Matthew Wild

UKSSDC - RAL Space

Co-Authors: S. F. James (UKSSDC - RAL Space) S. J. Pepler (CEDA - RAL Space)

Session: MIST: MIST General session

Presentation type: Poster

Summary:

The UK Solar System Data Centre has now been operating under joint funding by NERC and STFC for a year. As part of our integration within the NERC data centres structure, we need to conduct a data prioritisation exercise to determine the user communities requirements and wishes for the varied historical and current datasets maintained within the UKSSDC. We are therefore conducting a survey of our users requirements and comments on the current UKSSDC service alongside a presentation of the range of data held.

Probing Geospace with VLF radio signals

Author: A. J. Kavanagh

Lancaster University

Co-Authors: M. Denton (Lancaster University); J. Denton (Headlands School and Community Science College); H. Harron (Headlands School and Community Science College)

Session: MIST: MIST General session

Presentation type: Poster

Summary:

The STFC Public Engagement Programme

Author: Dr Robin Clegg

Science and Technology Facilities Council

Co-Authors:

Session: OUT: Outreach

Presentation type: Talk

Summary:

I will describe STFCâ€™s Science in Society/Public Engagement (PE) programme, covering our new strategy â€˜Inspire and Involveâ€™, drivers and target audiences, funding schemes, support for astronomers and space scientists, schoolsâ€™ and community programmes. I will summarise grants policy, where through â€˜Pathways to Impactâ€™ grant applicants need to consider knowledge exchange and public engagement, and can apply for funds for PE work. The collective (RCUK) programme has resulted in the Beacons for PE, the PE Manifesto, a National PE Concordat, and several national schemes. The Large Hadron Collider UK engagement programme, a partnership with particle physicists and CERN, perhaps showed what can be done in a â€˜campaignâ€™. STFC values partnership with its research communities, and this is a chance for you to comment on this programme of working together.

Using fiction to communicate science

Author: Pippa Goldschmidt

Co-Authors:

Session: OUT: Outreach

Presentation type: Talk

Summary:

Creative residencies in academic environments can provide ways of engaging with subject matter previously thought of as â€˜inaccessibleâ€™ by some audiences. This engagement happens at different interfaces, first between the writer and the academics, and then outwardly with different audiences such as other writers, other academics, and the general public. Using my own experience, I will show how writer-in-residence posts at universities can engage new audiences in exploring science, through encouraging the individual and collective activities of reading and writing fiction based on and inspired by science. I will talk about the outcomes of different activities I have carried out; such as running poetry and short story competitions, and organising workshops and public readings.

The Hot Spot at Jodrell Bank

Author: Tim O'Brien

University of Manchester

Co-Authors: Teresa Anderson (University of Manchester)

Session: OUT: Outreach

Presentation type: Talk

Summary:

We will report on a project to develop an innovative programme of public events and education at Jodrell Bank Observatory. Funded by an STFC Large Award this project ran from 2007 to 2011. It increased annual visitor numbers from 64,000 to 85,000 and enabled more than 5,000 schoolchildren to take part in workshops. The Hot Spot project was used to pilot and underpin the business plan for a new Discovery Centre at Jodrell Bank. This was awarded 2.9M pounds of regional funding in May 2010. Construction began in September 2010 and the Centre is due to open in April 2011.

Las Cumbres Observatory: keeping you in the dark!

Author: Edward Gomez

Las Cumbres Observatory Global Telescope Network

Co-Authors: S. R. Lowe (LCOGT)

Session: OUT: Outreach

Presentation type: Talk

Summary:

For the last 5 years Las Cumbres Observatory Global Telescope Network (LCOGT) has been preparing to roll out a global telescope network. 2011 will see substantial progress in building new telescopes at remote astronomical sites and the creation of citizen science programmes which will make use of this network. We've been working on ways that anyone can enjoy being a citizen scientist with LCOGT. You will not need to install lots of software or learn complicated procedures, just a web browser and a willingness to experiment.

Making Space in the timetable

Author: Charles Barclay

Marlborough College and Oxford Astrophysics

Co-Authors:

Session: OUT: Outreach

Presentation type: Talk

Summary:

We are unique in the UK in having qualifications which allow study of Astronomy as a separate subject in the timetable at Secondary level. If the enthusiasm and interest in Astronomy seen (almost without exception) at ages 10 and 11 can be maintained, pupil numbers in Science at KS4 may be supported and Astronomy at this level is equally appealing to both girls and boys. The GCSE continues to grow exponentially and the new Specification, implemented in 2009 with a first exam in 2011 looks to see a further hike in pupil numbers. The new Extended Project initiative at KS5 also allows for in-depth pupil motivated study of astronomical topics in the sixth form and thus offers scientific subject continuation post-16. I shall illustrate how the Royal Astronomical Society with ESERO-UK and the Institute of Physics among others are now in a position to support, and via a mapping exercise of all educational outreach in astronomy in England and Wales, build local frameworks and co-ordinate existing outreach efforts.

The Aberystwyth Physics Buskers: An ongoing public outreach scheme

Author: James Andrew Carter

Aberystwyth University

Co-Authors: M.J.Vickers

Session: OUT: Outreach

Presentation type: Talk

Summary:

The Aberystwyth Physics Buskers are a group of postgraduate-led physics undergraduates. They have been trained in science busking, a tool for science outreach used to communicate simple physics to children in a low-tech, low-cost manner. The results of this scheme, both in terms of outreach output and the development of the scheme's participants, is presented here.

Making magic: show-stopping interactivity with Arduino and Quartz Composer

Author: Dr Andrew Pontzen

Institute of Astronomy, Cambridge

Co-Authors:

Session: OUT: Outreach

Presentation type: Talk

Summary:

Arduino is an open-source hardware platform which allows rapid development of small-scale embedded computers with custom hardware inputs and outputs. Quartz Composer is a technology built into Mac OS X which allows rich, interactive graphics to be built into live presentations. This talk will outline how combining such hardware and software platforms allows for show-stopping demonstrations in live talks. As an example I will demonstrate a live simulation of quantum entanglement which I have performed to groups ranging up to 800 students (for The Training Partnership at the Institute of Education). This kind of technology has almost limitless potential to spawn rich interactive demonstrations for both small-scale and large-scale science communication: the talk will close with some pointers for possible future projects.

The Society for Popular Astronomy - A call for science communicators

Author: Mandy Bailey

Keele University

Co-Authors: Primary author: E.Baldwin (Astronomy Now/Young Stargazers Section Director, SPA) Co-authors: M.Bailey (Keele University/SPA Publicity Officer); R. Scagell (SPA Vice-President); H. Walker (RAL/SPA Treasurer); J. Zarnecki (Open University/SPA President).

Session: OUT: Outreach

Presentation type: Talk

Summary:

The Society for Popular Astronomy's youth section, the Young Stargazers, is a relatively new section of the society aimed at attracting the under 16s. To this end, we offer a discounted membership rate and a welcome pack which includes a file of 'getting started in astronomy' information sheets, observing guides, projects and more. At least three pages of content in the society's bi-monthly magazine, Popular Astronomy, are dedicated to our Young Stargazer members. We encourage them to contribute by writing articles, book reviews or even presenting their projects at one of our meetings. We also strive to produce a summer holiday activities pack and other updates to the welcome file throughout the year. Currently run by a very small team of volunteers, we are looking for keen science communicators who wish to add to their CV by contributing content to the Young Stargazer team â€“ with a view to perhaps becoming a permanent member of the team â€“ to help drive this growing and vital section of the Society as it approaches its 60th anniversary year. This talk will outline the aims and aspirations of the Young Stargazers section and present the opportunities available to potential volunteer contributors. (To be presented by Emily Baldwin)

Working together - better

Author: Dr Marek Kukula

Royal Observatory Greenwich

Co-Authors: D. Hillier (Royal Observatory Edinburgh); R. Massey (Royal Astronomical Society); S. Owens (Freelance science communicator); H. Walker (Rutherford Appleton Laboratory)

Session: OUT: Outreach

Presentation type: Talk

Summary:

Building on the successes of initiatives such as International Heliophysical Year 2008, International Year of Astronomy 2009 and BBC Stargazing Live this talk will be an update on work to enhance collaboration between the various national organisations with leading roles in public and school engagement with astronomy. How can we work together in the long term and ensure that news, ideas, resources and best practice are shared effectively?

Down2Earth!

Author: Dr Sarah Roberts

Faulkes Telescope Project, University of Glamorgan

Co-Authors: P. Roche (Faulkes Telescope Project, University of Glamorgan)

Session: OUT: Outreach

Presentation type: Talk

Summary:

In this talk I will summarise the Down2Earth (D2E) project. D2E targets secondary school students (currently ages 11-16), using exciting astronomy/planetary science topics such as the study of asteroids and comets impacting on the Earth. The current project consists of paper-based resources, aimed specifically at Key Stage (KS) 3 and 4 Science students, and loan boxes containing samples of meteorites, rocks and dinosaur fossils which can be sent out to schools across Wales through the Museumâ€™s loan service. Another aspect of the D2E project which has proven immensely popular is the interactive "Impact Calculator": http://education.down2earth.eu/impact_calculator/ where students choose the size, density, angle and velocity of an impactor, smash it on the Earth and see the size and effects of the crater formed and kinetic energies involved in such an impact. All resources are bilingual, and some materials are also available in formats for the visually impaired, given the tactile nature of meteorites.

ESERO-UK - The UK Space Education office

Author: Dr Allan D Clements

ESERO-Uk: The UK space education office

Co-Authors:

Session: OUT: Outreach

Presentation type: Talk

Summary:

This talk will describe the work of ESERO-UK which aims to enhance and support STEM teaching and learning in UK schools by using space as a context. Key deliverables are: To share good practice and space related teaching and learning resources with teachers and college lecturers. Develop ESERO-UK as the first point of contact for the education and space communities when seeking information about space education and careers. Raise the profile of ESA, the UK Space Agency and the wider UK Space Community with schools and colleges. Create a website to promote the ESERO-UK and its teaching and learning resources to educators throughout the UK. Establish space education ambassadors for the countries and regions within the UK to build and maintain space education networks that bring coherence to the space education community and provides support to schools and colleges. Make ESA and other space education resources (subject to copyright approvals) available to teachers via the National STEM Centreâ€™s eLibrary and networks. Set up a physical collection of space education resources at the National STEM Centre. ESERO-UK as part of the National STEM Centre is also working with RAS to help promote astronomy resources within UK schools.

The UK Herschel Outreach Programme

Author: Dr Peter Hargrave

Cardiff University

Co-Authors: Dr Chris North, Prof Matt Griffin

Session: OUT: Outreach

Presentation type: Talk

Summary:

The Herschel Space Observatory was launched in May 2009, and recently celebrated one year of spectacular science results. We have developed an extensive outreach programme for the Herschel mission in the UK, capitalizing on the many outreach and education opportunities afforded by the science and engineering involved throughout the mission. I will present details of this programme, and discuss the success (or otherwise) of the various aspects.

Astronomy Outreach

Author: Shaaron Leverment

British Association of Planetaria

Co-Authors:

Session: OUT: Outreach

Presentation type: Talk

Summary:

Planetaria are on the front line of astronomy outreach. A planetarium dome is one of the very best tools for astronomy education and across the UK, static and mobile planetarium domes see thousands and thousands of schools children and members of the public every day. Find out more about the work they are doing, the recent changes and advancements with equipment used and how you can get involved.

Amateur collaborations in the field of comet recovery and monitoring using Faulkes Network

Author: Nicholas Howes

Astronomy Now Magazine

Co-Authors: E.C.Baldwin (Astronomy Now)

Session: OUT: Outreach

Presentation type: Poster

Summary:

Comet C/2007 Q3 (Siding Spring) was discovered by Donna Burton in 1986. During the course of its last opposition, amateur astronomer Nick Howes using the 2m Faulkes Telescope in Hawaii along with professional observatories in France and Italy independently and simultaneously detected a significant break up in the comet nucleus. The resultant global media attention and further observations of both this comet and Comet 103P Hartley, where Howes independently calculated the comet rotation speed using rotational gradient processing in commercial software show that professional/amateur collaborations are still important in the field of astronomy, and how, by using amateurs with their unlimited telescope time as the driving force behind projects, outreach and education gains an interface to the world of high end astronomy.

Making the most of a poster to attract non-scientific audience

Author: Santiago Vargas Dominguez

Mullard Space Science Laboratory (UCL)s

Co-Authors:

Session: OUT: Outreach

Presentation type: Poster

Summary:

Attracting people without a scientific background to read a poster about science research is not an easy task. It is tricky to strike the optimum balance between aesthetics and the need to convey complex concepts.Â  Overall such posters should provide an enjoyable experience for the viewer. Apart from the content, some thought should be put in to creating an innovative design including eye-catching images to clarify ideas and highlighting key phrases to make the poster more digestible. Stating the relevance and importance of your research to the reader helps, too. This poster presents cutting-edge research about the magnetic behaviour of the Sun in a style that makes it very attractive to a wide audience by including interactive pop-ups that can be manipulated by the viewer to discover new information.

Astronomy Question Of The Day

Author: Dimitri Veras

Institute of Astronomy, University of Cambridge

Co-Authors:

Session: OUT: Outreach

Presentation type: Poster

Summary:

I present an interactive website which engages all people through the use of astronomical trivia, where the primary educational component is the explanation of the answers. The website emphasizes simplicity and ease of use, and aims to allow both young children and seasoned astronomers, as well as all others, to be challenged and have a fun experience. Two questions will be asked each weekday, along with answer explanations for the previous day's questions. Properly accredited photographs are used whenever possible in these explanations. One line of questions is part of a competition which includes "lifelines" and a running tally, and requires user registration. The competition also includes risk assessment and user input. All questions are archived on the site for public use.

Spatially resolved submm imaging of the HR 8799 debris disk

Author: Jenny Patience

University of Exeter

Co-Authors: J. Bulger (1), R. R. King (1), B. Ayliffe (1), M. R. Bate (1), I. Song (2), C. Pinte (3), J. Koda (4), C. D. Dowell (5), A. Kovacs (6), & J. Carpenter (5) 1- Exeter, 2 - Georgia, 3 - Grenoble, 4 - Stonybrook, 5 - Caltech, 6 - Minnesota

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

With the Caltech Submm Observatory (CSO) and the CARMA array, we have observed the HR 8799 debris disk at 350um and 1.3mm. The 350um map is the first spatially resolved measurement of the debris disk encircling the HR 8799 planetary system. Both the 350um flux and the arc of emission offset from the position of the star are consistent with a Kuiper belt of dust extending from ~90-300 AU. Although the resolution of the current map is limited, the distance to the brightest part of the disk and the asymmetric shape is similar to the pattern expected for submm-emitting grains trapped in a 2:1 mean motion resonance with the outermost planet. If resonant dynamical interactions are confining the dust, then planet migration may have enhanced the trapped dust population, and the current eccentricity of the planet must be low for the pattern to persist for the lifetime of the system. Another scenario for producing a non-resonant clumping of dust particles is an undetected eccentric, Earth-mass outer planet, exterior to the imaged giant planets.

Early highlights from the Herschel DEBRIS survey

Author: Bruce Sibthorpe

UK Astronomy Technology Centre

Co-Authors:

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

In this talk I will present the current status of, and recent highlights from, the DEBRIS Herschel key programme. DEBRIS is an unbiased far-infrared survey of approximately 500 nearby stars, with the goal of providing a statistically robust set of debris disc detections. In this talk I will describe some early results from the survey, including modelling of resolved sources, as well as some preliminary statistical results.

Debris discs around A type stars: Preliminary results from the DEBRIS survey.

Author: Nathalie D. Thureau

School of Physics and Astronomy, University of St Andrews

Co-Authors: J.S. Greaves (School of Physics and Astronomy, University of St Andrews); G.M. Kennedy (Institute of Astronomy, University of Cambridge); B.C. Matthews (Herzberg Institute of Astrophysics, University of Victoria); N.M. Phillips (Institute for Astronomy, Royal Observatory Edinburgh) B. Sibthorpe (UK Astronomy Technology Centre, Royal Observatory Edinburgh); and DEBRIS team

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

We present the preliminary results of PACS (Photodetector Array Camera and Sprectrometer)100 and 160 microns high angular resolution imaging of the debris discs around a sample of 130 A type stars. This study is part of the Herschel DEBRIS (Disc Emission via a Bias-free Reconnaissance in the Infrared/Submillimetre) project which is targeting an unbiased sample of A-M stars. The aim of the study is to discover and characterise the cold Kuiper belt like debris discs surrounding these stars. Debris discs are the remnant from the planet formation. They can be detected through the thermal emission from the large amount of dust in the discs. The unprecedented sensitivity and angular resolution of Herschel will allow to shed new light on the occurrence and the physical properties of debris discs around A stars.

Planets around white dwarfs: detections at last

Author: Matt Burleigh

University of Leicester

Co-Authors:

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

I will present the latest results from surveys to find planets around white dwarf stars, from direct imaging to pulsation timing, including likely detections and statistics, and discuss the implications for our understanding of planet formation and solar system evolution at a wide range of stellar masses.

Ultracool Companions to White Dwarfs: Probing the Substellar Graveyard

Author: Paul Steele

Max-Planck-Institut fÃ¼r extraterrestrische Physik

Co-Authors: M.R.Burleigh (University of Leicester); P.D.Dobbie (AAO); R.F. Jameson (University of Leicester)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

We present the latest results in a near-infrared photometric search for unresolved cool companions to white dwarfs in UKIDSS. Twenty five DA white dwarfs were identified as having multiple excesses indicative of a low mass companion, with 8-10 of these having a predicted mass range associated with brown dwarfs. Spectroscopic follow-up will be presented for a number of these candidates. The results of this survey show that the unresolved (<2'') brown dwarf companion fraction to DA white dwarfs is 0.2-0.8%.

High-angular resolution spectro-imaging of planetary formation and exoplanets with the VLTI

Author: Francoise Delplancke

European Southern Observatory

Co-Authors: G. van Belle, M. Wittkowski, C. Hummel (ESO)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

The Very Large Telescope Interferometer with its high-angular resolution (down to a couple of milli-arcseconds) and with its versatile instrument suite (from J- to N-band with spectral resolution) is an instrument of choice for the observation of the inner regions of proto-planetary nebulas and for the detection of extra-solar planets. Interferometry is not a simple technique but huge efforts have been made at ESO and in the community to make this method accessible to any astronomer, including image reconstruction packages that streamline the data processing. We will present the capabilities of the VLTI in its present state and when the second generation instruments will be installed (2014+) with specific attention to their impact on the fields of exoplanets and planetary formation. Recent scientific highlights and their impact on the field will also be presented, including mid-infrared MIDI and near-infrared AMBER observations of high mass young stellar objects.

Recent results from the Gemini-NICI campaign

Author: Fraser Clarke

University of Oxford

Co-Authors: M.Tecza (University of Oxford), N.Thatte (University of Oxford), M.Lui (University of Hawaii), B.Biller (MPIA, Heidelberg), Z.Wahhaj (University of Hawaii), The NICI campaign constortium.

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

We report on progress of the Gemini-NICI planet imaging campaign, which has searched for planets around ~200 nearby stars at unprecedented sensitivity. Many candidate systems have been discovered, and we are now in the process of confirming these via 2nd-epoch observations to reject background contaminants. I will also summarize the two confirmed candidates detected and published so far -- one of the coolest young 'benchmark' brown dwarfs yet discovered, and a young brown dwarf companion to PZ Tel B on a highly eccentric orbit.

Finding halo T dwarfs in UKIDSS

Author: David Murray

University of Hertfordshire

Co-Authors: B. Burninghahm (University of Hertfordshire), H.R.A Jones (University of Hertfordshire), D.J. Pinfield (University of Hertfordshire), P.W. Lucas (University of Hertfordshire), S.K. Leggett (Gemini Observatory), .G. Tinney, A.C. Day-Jones (Universidad de Chile), D.J. Weights (University of Hertfordshire), N. Lodieu (IAC), J.A. Perez-Prieto (IAC), Z.H. Zhang (University of Hertfordshire), J.R.A. Clarke (University of Hertfordshire), J.S. Jenkins (Universidad de Chile), M. Tamura (NAOJ)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

The substellar population of the galactic halo has implications for the formation and evolution of stars and brown dwarfs. In the hope of identifying halo T dwarfs, we undertook a search of UKIDSS for metal-poor T dwarfs. We identified twelve spectroscopically-confirmed brown dwarfs. Amongst these, we also found the first two kinematic halo candidates. We required H-K < -0.2, as blue near-infrared colours have been attributed to collisionally-induced hydrogen absorption, which is enhanced by either low metallicity and high surface gravity. Collisionally-induced hydrogen absorption results in T dwarf spectra with depressed K-band peaks. In addition to our spectroscopy, second-epoch images allowed us to calculate proper motions for our objects. In combination with distance estimates, we derive tangential velocities U and V components for our objects. We found that ULAS J0926+0835 has U = 62 km/s and V = -140 km/s and ULAS J1319+1209 has U = 192 km/s and V = -92 km/s, both of which are halo-like. Surprisingly however, the object with the most depressed K-band, ULAS J1233+1219, has disc-like kinematics and thus does not appear to be a member of the halo. We also present a detailed description of the metal-poor benchmark Hip 73786B.

Exoplanetary Eccentricity Excitation During Post-Main Sequence Stellar Evolution

Author: Dimitri Veras

Institute of Astronomy, Cambridge University

Co-Authors: M. C. Wyatt (Institute of Astronomy, Cambridge University)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

Extrasolar planets orbiting stars that have already turned off of the main sequence are being discovered in increasing numbers. Understanding the fate of these planets can aid future observations and provide a more accurate global view of the types of exosystems which may exist. Here, we demonstrate how single planets with long periods as well as cometary clouds may become unstable or severely disrupted based on orbital dynamics alone, even at the exclusion of tidal effects and body structure information. We provide a detailed treatment of the variable-mass two-body problem, and discuss the implications by applying the findings to single-planet systems around stars of all spectral types.

Characterising Sodium in the Hot Jupiter HD189733b

Author: Mrs Catherine Huitson

University of Exeter

Co-Authors: D.K.Sing (University of Exeter, UK); A.Vidal-Madjar (CNRS, Institut d'Astrophysique de Paris, France); A.Lecavelier des Etangs (CNRS, Institut d'Astrophysique de Paris, France); J-.M.Desert (Harvard-Smithsonian Center for Astrophysics, USA); G.E.Ballester (University of Arizona, USA)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Poster

Summary:

The only previous detection of sodium in the atmosphere of HD189733b was ground-based. Space based observations have the advantage of measuring absolute absorption depth, and HST STIS observations were taken for this purpose. Using the G750M grating, the preliminary absorption depth of sodium in the upper atmosphere is (51.1Â±6.0)x10-5, in good agreement with the previous measurement. The resolution allows us to construct a profile of the line shape and we detect the line core but without any broad wings. We have found that the effects of occulted starspots on the absorption profile and depth are not significant. Previous discovery of a global haze indicates that the sodium we are seeing is high in the atmosphere, above this cover, and we are now fitting the line profile to determine how the temperature changes with altitude. Predictions expect very high temperatures could be seen in the upper atmosphere where stellar UV radiation is unable to escape. This will provide a good comparison to HD209458b, the only other planet that has been profiled in this way, and which has very different atmospheric properties to HD189733b.

N-body simulations of low, intermediate and high mass (gas giant) planet formation.

Author: Phil Hellary

Queen Mary, University of London

Co-Authors: R. P. Nelson (Queen Mary, University of London)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

I will present the results of recent simulations of planetary systems formation. The simulations were performed using an N-body code, and include prescriptions for the migration of low and high mass planets, collisional accretion between protoplanets and/or planetesimals, and gas accretion onto planetary cores that form during the simulations. Particular emphasis is placed on the role of migration driven by corotation torques operating in radiatively inefficient discs, whose influence can prevent the rapid inward migration of growing protoplanets. Our models lead to the formation of systems containing low, intermediate, and high mass (gas giant) planets, and may provide an interesting explanation for giant planets that orbit at large distances from their host stars.

Bayesian Techniques for Exoplanet Characterisation

Author: Morgan Hollis

UCL

Co-Authors: O.Lahav (UCL); G.Tinetti (UCL)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Poster

Summary:

Bayesian statistical methods have found many applications in recent years, particularly in cosmology, and are now rapidly being adopted in the area of exoplanets. Here is presented a brief overview of the Bayesian theory, and the Markov Chain Monte Carlo (MCMC) approach to calculating the full posterior distribution in a multi-dimensional parameter space. The theoretical model and the software used to apply the technique, as originally presented by Balan & Lahav (2009), are described, and the results of tests of the software and the initial application to one extrasolar system are shown. It was found that the program performed well in tests using mock data, and was able to accurately recover an input model from simulated data with noise.

The shocking UV transit of WASP-12b: A new approach to measuring exoplanetary magnetic fields.

Author: Joe Llama

University of St Andrews

Co-Authors: K. Wood (University of St Andrews), A. A. Vidotto (University of St Andrews), M. M. Jardine (University of St Andrews), Ch. Helling (University of St Andrews)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Poster

Summary:

We present Monte Carlo radiation transfer simulations of a planet and magnetospheric bow shock transiting a limb-darkened star. We investigate various shock geometries, orientations and densities. Our models accurately reproduce the early ingress observed in WASP-12b, one of the largest transiting exoplanets discovered to date. The results show bow shocks could be a common occurrence amongst hot-Jupiter systems and should provide us with a greater insight into the structure and strength of planetary magnetic fields.

Life & Light: Exotic Forms of Photosynthesis in Binary & Multiple Star Systems

Author: Jack O

University of St Andrews

Co-Authors: J.A.Raven (University of Dundee); C.S.Cockell (Open University); J.S.Greaves (University of St Andrews)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Poster

Summary:

The potential for hosting photosynthetic life on Earth-like planets within binary/multiple star systems was evaluated by modelling levels of photosynthetically active radiation (PAR). Combinations of M and G stars in: (i) close-binary systems; (ii) wide-binary systems and (iii) three-star systems were explored. A range of stable radiation environments were found to be possible, which allow for the prospect of familiar, but also more exotic forms of phototrophic life, such as infrared photosynthesisers and organisms specialised for specific spectral niches.

Eclipsing binaries and astrophysical false positives in the PLATO fields

Author: Robert Farmer

Open University

Co-Authors: Kolb,U (Open University);Norton, A (Open University)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Poster

Summary:

We perform binary population synthesis calculations linked to a comprehensive Galactic extinction model to determine the number and type of eclipsing binaries expected in a given field of view with a given magnitude limit. We present selected, preliminary results on fields that are representative of the central, most sensitive region of the proposed PLATO space mission. Our technique has two principal applications: (1) Estimating the number and nature of astrophysical false positive exoplanet transit detections. 2) Constraining the formation history of binary systems by comparing the synthesised signal with a census from an actually observed field.

Roche Lobes of Hot Jupiter Exoplanets

Author: R. Busuttil

Open University

Co-Authors: C.A.Haswell (Open University)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Poster

Summary:

The hot Jupiter exoplanets orbit very close to their host stars, and consequently have some similarities to compact binary star systems. For example, the Roche model, which uses the gravitational and centrifugal forces to calculate the equipotentials in the co-rotating frame, is useful in their analysis. In the Roche model, material within the planetâ€™s Roche lobe will be bound to the planet; if the planetâ€™s Roche lobe is over-filled, mass transfer is expected. Several hot Jupiter exoplanets are surrounded by extended exospheres of diffuse neutral gas, detected by the strong absorption it produces in UV resonance lines. In several cases, this gas appears to overfill the planetâ€™s Roche lobe. Several models have been proposed for the origin of the extended exospheric gas: a hydrodynamic â€œblow-offâ€ caused by the strong irradiation from the host star; tidal disruption of the planet; entrainment of coronal material in the planetâ€™s magnetosphere; charge-exchange reactions with stellar wind particles. We present comparisons of the transit-inferred radii of hot Jupiter planets and their exospheres with their Roche lobes, and discuss what this implies for the mechanisms underlying the exospheric gas.

Investigating planetary statistical distributions

Author: Alex Pettitt

University of Exeter

Co-Authors:

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Poster

Summary:

Since the release of the Kepler planetary candidates the number of possible Earth-like planets has experienced a huge expansion. We look at the recently published data from Kepler and compare the statistical ensemble to the existing planets discover by different radial velocity, with a specific focus on candidates from the HARPS GTO survey and specifically in the range of masses bellow that of Saturn. The overall purpose of which is to obtain a mass-radius relation for planetary companions which can be used as a test for current planetary formation models.

White Dwarfs in the WTS

Author: Paul Steele

Max-Planck-Institut fÃ¼r extraterrestrische Physik

Co-Authors: R. Saglia (MPE), J. Koppenhoefer (MPE), D. Pinfield (University of Hertfordshire)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Poster

Summary:

We have identified candidate white dwarfs in the WFCAM Transit Survey using Optical to Near-Infrared colours and reduced proper motion. We have analysed the light curves of these stars using standard transit search algorithms and present here the initial results.

Young Stars in N2362: A Spectroscopic and Photometric Study

Author: Lauren M. Weiss

Institute of Astronomy, University of Cambridge

Co-Authors: S. Hodgkin (Institute of Astronomy); M. Irwin (Institute of Astronomy); J. Birkby (Institute of Astronomy); R. Jackson (Keele University); R. Jeffries (Keele University)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Poster

Summary:

We combine photometric and spectroscopic observations of star cluster NGC 2362 to analyze the statistical properties of stars in this young (~5 Myr) cluster. The candidate cluster members we study are cool (K-type and later) and small (0.1 < M < 1.2). The evolution of young stars in this mass range, specifically the mass-radius relation, is poorly understood due to the dearth of observational constraints. Observations of binary systems in the cluster allow for accurate mass measurements. Our photometric data of 271 candidate cluster members were obtained at the CTIO 4-m Blanco telescope with the Mosaic-II detector. We use multi-epoch spectroscopic data from the ESO VLT telescope, obtained through the GIRAFFE/FLAMES multi-fibre spectrograph on nine nights in December 2007, to study the radial velocities of 116 stars in the cluster field. Measuring their velocities allows us to determine which stars are cluster members and which are outliers (i.e. foreground or background field stars), which improves upon the color-magnitude selection done in previous work. Additionally, we present a preliminary analysis of the eclipsing and spectroscopic binaries in this cluster.

A Variability Survey of Bright Stars on the Ecliptic Plane with STEREO

Author: Danielle Bewsher

University of Central Lancashire

Co-Authors: K.T. Wraight (1), G.J. White (1,2), D. Bewsher (3), A.J. Norton (2) (1) Department of Physics and Astronomy, The Open University, Milton Keynes, MK7 6AA, UK (2) Space Science and Technology Department, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, UK (3) Jeremiah Horrocks Institute, University of Central Lancashire, Preston, Lancashire, PR1 2HE, UK

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Poster

Summary:

The STEREO mission is able to deliver photometric measurements of stars in the field of view of the satellites' Heliospheric Imagers. The combination of moderately stable photometry, extended continuous viewing periods with moderate cadence and repeated visits is able to provide useful data for stellar variability studies of bright stars (R<12) in the Ecliptic Plane outside the field of view of other surveys. The poster will illustrate this with clear lightcurves of different types of variables.

Anglo-Australian Planet Search

Author: Hugh Jones

University of Hertfordshire

Co-Authors: Jeremy Bailey (University of New South Wales), Paul Butler (Carnegie Institution of Washington), Brad Carter (University of Southern Queensland), James Jenkins (University of Chile), Chris Tinney (University of New South Wales), Rob Wittenmyer (University of New South Wales)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Poster

Summary:

The Anglo-Australian Planet Search began operation in 1998 January, and is currently surveying 250 stars. It has discovered some 36 exoplanets with m sin i ranging from 5.1 MâŠ• to 10 MJup. Latest discoveries and results from our simulations of the underlying exoplanet population will be reported. In particular, the focus will be on the contraints that we can place on the underlying population of Earth-like and Jupiter-like exoplanets in orbit around nearby stars

Modelling the chemistry of a gravitationally unstable protoplanetary disc

Author: John Ilee

University Of Leeds

Co-Authors: A. Boley (University Of Florida) P. Caselli (University Of Leeds) R. Durisen (Indiana University) T. Hartquist (University Of Leeds) J. Rawlings (University College London)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Poster

Summary:

Until now, axisymmetric, $\alpha$-disc simulations have been adopted to describe the dynamics used in the construction of chemical models of protoplanetary discs. While this approach is reasonable for many discs, it is not appropriate for young, massive discs in which self-gravity is important. Spiral waves and shocks cause significant temperature and density variations which affect the chemistry. We have used a dynamical model of solar mass star surrounded by a massive (0.39 M$_$), self-gravitating disc to model the chemistry of one of these objects.

Gravitational microlensing, planet populations, and an agenda of exploration

Author: Martin Dominik

SUPA, University of St Andrews

Co-Authors:

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

While detections of more than 500 planets have been reported, statistical assessments of planet populations are still in their infancy. A vast complexity is encountered due to planet populations being a function of the properties of the respective host stars, and planetary systems being structured. Moreover, obtaining well-defined samples rather than just detecting planets requires more elaborate experimental designs. Under these aspects, I will discuss recent results from gravitational microlensing, which crucially complement what we are learning from transit searches and radial-velocity measurements, which are blind to regions of planet parameter space that are accessible by microlensing. In fact, emerging efforts are set to investigate the abundance of planets below Earth mass, with a hard limit being as low as the mass of the Moon. We are now being given opportunities for exploration that could have only be dreamt of a few decades ago, but do we have the right approach for finding answers, and do we ask the right questions?

Transiting Planets : The Mass Problem

Author: Dimitris Mislis

Institute of Astronomy - University of Cambridge

Co-Authors: S. Hodgkin (Institute of Astronomy - University Cambridge )

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

We present a new approach to determine the parameters of transiting extrasolar planetary systems using photometric light curves (LCs). An analysis that combines a treatment of various phenomena in high-accuracy LCs allows a derivation of orbital and physical parameters. Our method considers the primary transit, the secondary eclipses, and the overall phase shape of a LC between the occultations. Phase variations are induced by reflected and thermally emitted light from the planet. Moreover, the ellipsoidal shape of the star due to the gravitational pull from the planet as well as the Doppler shift of the light on the CCD induce phase variations. As we find, the complete decipherment of LCs yields information about the planetary mass, orbital eccentricity, orientation of periastron, and the planetâ€™s albedo. These parameters were impossible to extract from low-accuracy data of ground-based surveys.

Probing the atmosphere of the warm Neptune GJ 436-b

Author: Camilla Danielski

UCL

Co-Authors: G. Tinetti (UCL), J.P. Beaulieu (IAP, UCL), D. Kipping (UCL), J. Tennyson (UCL)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

We present here the analysis of ten secondary eclipses of the hot-Neptune GJ 436-b at 8 micron with the InfraRed Array Camera (IRAC) on board the Spitzer Space Telescope. We reduced the data recorded at different epochs and compared them to test planetary or stellar variability over time. Our analysis shows that the differences among the eclipse depths are negligible and all the values obtained are consistent at 1Ïƒ level (Danielski et al. in prep.). Our results indicate no variability and a quite star/atmosphere of GJ 436-b. We discuss the outcome of our work in the light of a similar study performed by Agol et al. (2010) on a different hot-Jupiter âŽ¯HD 189733b.

The WFCAM Transit Survey

Author: Brigitta SipÅ‘cz

University of Hertfordshire

Co-Authors: D.Pinfield (University of Hertfordshire) and members of the EC funded RoPACS Initial Training Network and of the WTS consortium

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

The WFCAM Transit Survey (WTS) has been obtaining data on the United Kingdom Infrared Telescope since 2007. Operating in the near-infrared the WTS targets about 6000 M dwarf stars (J<16) over several square degrees of sky and aims to find planets, down to the size of the Earth, transiting M dwarfs with periods up to a few days. In my talk I will present the goals and current status of the survey, our follow-up strategy and summarize the status of our most promising candidates.

Sensitivity analysis of the WFCAM Transit Survey

Author: GÃ¡bor KovÃ¡cs

Institute of Astronomy

Co-Authors: S.Hodgkin (Institute of Astronomy) and members of the EC funded RoPACS Initial Training Network and of the WTS consortium

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

The WFCAM Transit Survey has been running on the United Kingdom Infrared Telescope since 2007. The WTS targets about 6000 M dwarfs (J<16) in four fields close to the galactic plane in the near infrared. The search for planets around M dwarfs is a young and exciting field in exoplanet hunting. Core accretion theories predict that Jovian planets should be rare in systems around low mass stars. I will present my ongoing work on analyzing the sensitivity of our survey. A Monte Carlo simulation was developed using lightcurves in one of our fields to measure transit recovery ratios and to place statistical constraints on the frequency of different planetary systems around M dwarfs.

Ensemble asteroseismology of solar-type stars with the NASA Kepler Mission

Author: William Chaplin

University of Birmingham

Co-Authors: (On behalf of the Kepler Asteroseismic Science Consortium, KASC)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

We are entering a golden era for stellar physics, driven by new satellite and telescope observations of unprecedented quality and scope. New insights are being made possible by asteroseismology, the study of stars by observation of their natural, resonant oscillations. The recent launch of the NASA Kepler Mission has realized a huge breakthrough in amount and quality of data for the asteroseismic study of stars. Here, I report that the asteroseismic survey of solar-type stars undertaken by Kepler has met with unprecedented success, yielding detections of solar-like oscillations in ~500 stars. I present initial results on the exploitation of these data for informing studies of stellar populations in the galaxy, and discuss the wide-ranging research now being undertaken with this unique ensemble, including use of the seismic data to characterise the properties of systems with exoplanets.

EChO, the Exoplanet Characterisation Observatory

Author: Giovanna Tinetti

University College London

Co-Authors:

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

ECHO, the Exoplanet Characterisation Observatory, is a M-class mission selected by ESA to undergo an initial assessment phase. EChO will be devoted to the characterisation of the atmospheres of exoplanets, enabling for the first time the physics and chemistry of these far away worlds to be studied in great detail. The sample of target planets includes gas and ice giants, and large terrestrial planets, in orbits close to their parent stars. EChO will be a cooled 1.2metre space telescope optimised to observe the combined light of stars and their planets, building on the experience of transit and combined light observations with Hubble, Spitzer and ground-based telescopes. Using mid- to high-resolution spectroscopy between 0.6 and 16 Î¼m, this mission will allow a detailed characterisation of the composition and thermal structure of a highly representative subset of known extrasolar planets. In particular, EChO will be able to detect potential biosignatures in the atmospheres of large terrestrial planets (Super-Earths) in the habitable zones of late type stars.

Characterising Super Earths with the ECHO spacemission concept

Author: Marcell Tessenyi

UCL

Co-Authors: M.Ollivier (IAS);G.Tinetti(UCL);J.P.Beaulieu(IAP)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

Transiting Super Earths orbiting M dwarfs are excellent targets for the prospect of studying potentially habitable extrasolar planets. While most of the currently known Exoplanets are of the Hot Jupiter and Neptune type, attention is now turning to these Super Earths. An example is GJ 1214b, found by Charbonneau et al. in 2009. These candidates offer the opportunity of obtaining spectral signatures of their atmospheres in transiting scenarios, via data obtained by ground based and space observatories, compared to simulated climate scenarios. With the recent selection of the Exoplanet Characterisation Observatory (EChO) mission by ESA for further studies, I present observational strategies and time requirements for a range of targets characterisable by EChO, with a view to Super Earths orbiting M dwarfs.

The Next Generation Transit Survey (NGTS) and Plato

Author: Matt Burleigh

University of Leicester

Co-Authors:

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

I will present the Next Generation Transit Survey, a collaboration between Queens University Belfast, the Universities of Leicester and Warwick, and the Observatoire de GenÃ¨ve to supercede WASP and search for Neptune-size transiting planets, and the ESA Plato mission to find transiting Earth-size planets around the nearest bright stars.

The early evolution of low mass stars and brown dwarfs

Author: Isabelle Baraffe

University of Exeter

Co-Authors:

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

My talk will focus on the early evolution of low mass objects. I will discuss the main uncertainties on current evolutionary models for low mass stars and brown dwarfs and the effects of rotation, magnetic field and early accretion history on young object's structure. I will also present possible solutions to the well known spread in HRD observed in star formation regions for objects of a few Myr old.

The Physical Properties of Young Brown Dwarfs and Planetary-Mass Companions

Author: Robert King

University of Exeter

Co-Authors: J. Patience (University of Exeter), R. De Rosa (University of Exeter), I. Baraffe (University of Exeter), T. Barman (Lowell Observatory), A. Kraus (University of Hawaii), and Michael Ireland (Macquarie University).

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

Low-mass companions to nearby young stars are particularly valuable since the primary provides constraints on the distance to and age of these low-mass objects, breaking the mass-age-luminosity degeneracy. We will present Râˆ¼1500 near-IR spectra for a set of young, low-mass brown dwarf and planetary-mass companions and a comparison with more evolved substellar companions. Our sample consists of the lowest mass imaged companions with ages of 2â€“30 Myr and estimated masses of 5â€“25 MJup. These companions represent the lowest mass objects in the 2â€“30 Myr age range for which it is possible to obtain high quality infrared spectra. We will then detail the observations and interpretation of the young, low-mass object 2M1207b, a young L dwarf with an estimated mass of ~10 MJup, but an anomalously low luminosity. Finally, we will also present our campaign to test models of the L-to-T transition by determining the fractional coverage and persistence of condensate clouds using L-band spectroscopic observations of these young L dwarfs and variability monitoring of field L and T dwarfs.

Structure and evolution of exoplanets: from super-Earths to super-Jupiters

Author: Gilles Chabrier

Ecole Normale Superieure de Lyon and University of Exeter

Co-Authors:

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

The number of newly discovered exoplanets increases at an impressive pace. About 10% of these objects transit their parent mass, providing stringent constraints on their internal structure, their evolution and possibly on their formation mechanism. In this talk, I will examine our present understanding of the internal structure and evolution of exoplanets but I will also address some puzzling, yet unanswered questions about several of these objects and examine the various physical mechanisms proposed to explain their unexpected properties. Finally I will address the expected signature of the formation mechanism of massive gaseous planets vs low-mass brown dwarfs and will argue that there is no mass limit between these two distinct populations but rather an overlap in mass.

Ground-based spectroscopy of extrasolar planets

Author: Ingo Waldmann

University College London

Co-Authors:

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

In recent years, spectroscopy of exoplanetary atmospheres has proven to be very successful. When in the past discoveries were made using space-born observatories such as Hubble and Spitzer, the observational focus continues to shift to ground-based facilities. This is especially true since the end of the Spitzer cold-phase, depleting us of space-borne eye in the infra-red. A trend certain to intensify in the years to come with projects like E-ELT and TMT on the horizon. So far several observational strategies have been employed from the ground. All of which are trying to solve the problems incurred by high systematic and telluric noise and are distinct in their advantages and dis-advantages. Using time-resolved spectroscopy, we obtain an individual lightcurve per spectral channel of the instrument. The benefits of such an approach are multifold since it allows us to utilize a broad spectrum of statistical methods. Using new IRTF data, in the K and L-bands, we will illustrate the intricacies of two spectral retrieval approaches: 1) the self-filtering and signal amplification achieved by consecutive convolutions in the frequency domain, 2) the component separation of statistically independent sources using information entropy. These novel techniques allow us to present new results on the hot-Jupiter HD189733b, showing strong methane emissions in both, K and L-bands at spectral resolutions of R ~ 400. Using data from the IRTF/SpeX instrument, we will discuss the implications and possible theoretical models of strong methane emissions on this planet.

Rocks and ice cubes: The building blocks of the Solar System?

Author: Iwan Williams

Queen Mary University of london

Co-Authors:

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

The current consensus is that large bodies were built up through the accumulation of smaller once. Inside the ice-line from refractory and metalic material and beyond primarily from ice.The end point were represented by incomplete build up as bodies in the asteroid belt and comet population. But are these so distinct? Numerous examples will be discussed of asteroid like bodies amongst the comets and comets within the asteroid belt. More detailed investigations suggest that collisions were common, and, more surprising are still taking place at the present time. Appart from the obvious consequence of preenting possible dangers to present-day Earth, there are also implications regarding the explanation for the presence of water on Earth and Mars.

Collisional Evolution of Irregular Satellites

Author: Grant Kennedy

IoA, Cambridge

Co-Authors: M. C. Wyatt (IoA, Cambridge)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

The Solar Systemâ€™s irregular satellite swarms have been colliding for billions of years, grinding themselves towards oblivion. We have developed a model for this evolution and applied it to both the Solar System populations and swarms that may exist around extra-Solar planets. In this contribution, I will focus on the implications of this model for our understanding of the Solar System populations, and describe our attempts to detect the collisional fragments with Spitzer and Herschel.

Constraints on the Migration of Jupiter and Saturn from the Terrestrial Planets

Author: Craig Agnor

Queen Mary University of London

Co-Authors: D.N.C. Lin (University of California Santa Cruz)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

Resonant orbital structures in the Kuiper and asteroid belts strongly suggest the solar system's giant planets underwent divergent orbital migration in the past. While the evidence for planetary migration is convincing, the specific timing, mode and duration of this dynamical restructuring of the solar system remain grossly unconstrained. Here we examine how the divergent migration of Jupiter and Saturn, due to the scattering of small planetesimals, perturbs the orbits of the terrestrial planets. Using analytic models and N-body simulations we have identified six secular resonances between an apsidal eigenfrequency of Jupiter and Saturn and the four eigenfrequencies of the terrestrial planets that occur as Saturn migrates outward from about 8AU to its observed orbit at about 9.5AU. Passage through these secular resonances excites the eccentricities of the terrestrial planets. The amplitude of the response is a function of both the eccentricities and migration rates of the giant planets. In this presentation we will discuss the how the terrestrial planets are perturbed by giant planet migration and how the observed dynamical state of the terrestrial planets constrains the mode and timing of the divergent migration of Jupiter and Saturn.

Saturn

Author: Leigh N. Fletcher

University of Oxford

Co-Authors: B.E. Hesman (University of Maryland), P.G.J. Irwin (University of Oxford), K.H. Baines (University of Madison-Wisconsin), T.W. Momary (Jet Propulsion Laboratory), G.S. Orton (Jet Propulsion Laboratory), A. Sanchez-Lavega (Universidad del Pais Vasco), F.M. Flasar (Goddard Space Flight Center)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

An enormous eruption of bright cloud material took place in Saturnâ€™s northern hemisphere in December 2010, which rapidly grew in size to encircle the entire planet in a matter of weeks. This huge springtime storm is only the sixth recorded event on Saturn, and the first to be scrutinised in the thermal infrared using a combination of ground-based imaging from the VLT, and orbital spectroscopy from the Cassini spacecraft. Spectra between 5 and 200 Âµm, sensitive to Saturnâ€™s thermal emission, are used to determine the stormâ€™s temperatures, windspeeds (vertically and horizontally) and chemistry, providing us with a three-dimensional view of this spectacular meteorological phenomenon. The evolving storm system is consistent with a single convective disturbance, deep within Saturnâ€™s condensation cloud decks, which propagated upward over hundreds of kilometres to disturb the upper troposphere and stratosphere. Indeed, the stratospheric â€˜beaconsâ€™ generated by localised atmospheric subsidence near the storm have created the largest thermal contrasts ever measured on Saturn, with stratospheric emission outshining the rest of the planet at certain wavelengths. By comparing planetary-scale disturbances on the giant planets, we gain insights into the temporal variability of planetary atmospheres both in our solar system and beyond.

Rosetta at Lutetia â€“ constraints on the existence of an asteroidal exosphere

Author: I.P.Wright

PSSRI, Open University

Co-Authors: D.J.Andrews, S.Sheridan, G.H.Morgan, S.J.Barber and A.D.Morse

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

In 2010 the Rosetta spacecraft, during its epic journey to rendezvous with, and ultimately land on, a cometary nucleus, flew past the asteroid 21 Lutetia. During this event we activated the Ptolemy instrument (a gas chromatograph-mass spectrometer system, included on the Philae Lander element of the mission) both as a dry run for on/near-comet operations, and also as part of a campaign to evaluate whether or not the asteroid has a detectable exosphere. We will describe the encounter and discuss the results.

Investigation of Space Weathering Timescales via Spectroscopy of Small Near-Earth Objects

Author: Dr. Samuel Duddy

University of Kent, Canterbury

Co-Authors: A. Fitzsimmons (Queen's University Belfast) H. Hsieh (Institute for Astronomy, Hawaii)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

During their dynamical evolution onto Near-Earth Object (NEO) orbits, silicate-dominated asteroids experience space weathering. Heavy-ion irradiation by the solar wind causes the spectra of these objects to become redder and the silicate-absorption bands to become weaker with time. Since smaller asteroids are more collisionally active and can potentially evolve onto NEO orbits quicker, it might be expected that small NEOs have physically younger surfaces than larger NEOs. Using the NTT+EFOSC2 and the WHT+ISIS we conducted a spectroscopic survey of >30 NEOs with diameters smaller than 300m. The wavelength range, 0.4 to 1.0 microns, covered the diagnostic features necessary to allow classification of the NEOs using the SMASS Taxonomy. We classified 55% of small NEOs as silicate-dominated S-class, 16.5% as X-types, 19.5% as C-types while 9% exhibited D to T-type spectra. Comparing the population of observed small silicate-dominated NEOs to larger silicate-dominated NEOs from the literature, we find that the two populations are indistinguishable, suggesting that small and large NEOs exhibit comparable levels of space weathering, indicating it is a rapid process, occurring faster than dynamical evolution, ~1 Myr. Our results indicate that tidal resurfacing of NEOs with significant regoliths may be comparable over all size ranges studied.

An archive of Solar System bombardment preserved in the lunar regolith

Author: Katherine Joy

Lunar and Planetary Institute

Co-Authors: D.A. Kring (Lunar and Planetary Institute, USRA), M.E. Zolensky (NASA Johnson Space Center), D.S. McKay (NASA Johnson Space Center), D. K. Ross (NASA Johnson Space Center).

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

The lunar surface is covered by a regolith produced by impact comminution of underlying rock. This boundary layer preserves a record both of the Moonâ€™s geological history, and its collisional evolution with impacting asteroids and comets. Individual layers within the regolith, like strata on Earth, can be used to deduce how that flux of impacting objects may have changed with time and fragments of projectiles found in the regolith offer important clues to the sources of exogenous material delivered to the Moon. The chemical and temporal properties of that debris can be used to constrain dynamical models of Solar System evolution and causes of impact spikes to the Earth-Moon system. Here, we present a study of regolith breccias collected by the Apollo 16 mission from the nearside Cayley Plains and Descartes Formation. We have used electron microprobe techniques to identify non-lunar compositionally â€˜exoticâ€™ rock and mineral fragments within these samples. In ancient (~3.8-3.5 Ga) regolith breccias 60016, 60019 and 61135 we have identified a suite of ultra-magnesian fragments that are consistent with material delivered to the Moon by primitive chondritic projectiles during the basin-forming impact epoch.

Astronomical and Astrobiological Records Preserved in Lunar Palaeoregolith Deposits

Author: Ian Crawford

Birkbeck College London

Co-Authors: S.A. Fagents (University of Hawaii), K.H. Joy (Lunar and Planetary Institute), M.E. Rumpf (2)(University of Hawaii)

Session: PLA: Formation and evolution of planetary systems (including Solar System)

Presentation type: Talk

Summary:

One of the principal scientific reasons for wanting to resume in situ exploration of the lunar surface is to access the record it contains of early Solar System history. Studies of Apollo samples have revealed that solar wind particles are efficiently implanted in the lunar regolith, which may therefore contain a record of the composition and evolution of the Sun. Recently, samples of the Earthâ€™s early atmosphere appear to have been retrieved from lunar regolith samples, and it has been suggested that samples of Earthâ€™s early crust may also be preserved there in the form of terrestrial meteorites. In addition to these local Solar System records, the lunar regolith may contain a record of galactic events, by preserving the signatures of ancient galactic cosmic ray (GCR) fluxes, and the possible accumulation of interstellar dust particles during passages of the Sun through dense interstellar clouds. All these records would potentially yield valuable astronomical information concerning the evolution of the Sun and its changing galactic environment, with astrobiological implications for the conditions under which life arose and evolved on Earth. We argue that this record will be best preserved in ancient, buried regolith (â€˜palaeoregolithâ€™) deposits, and that locating and sampling such deposits would be an important objective of future lunar exploration activities.

Solar Observations with LOFAR

Author: Christian Vocks

Astrophysikalisches Institut Potsdam

Co-Authors: G. Mann (Astrophysikalisches Institut Potsdam)

Presentation type: Talk

Summary:

The LOw Frequency ARray (LOFAR) is a novel radio telescope that consists of 18 core stations near Exloo in the Netherlands, 18 Dutch remote stations, and international stations all over central Europe. One of them is currently being set up in Potsdam. LOFAR is a radio interferometer for the frequency range of 30 - 240 MHz and will exceed the sensitivity and resolution of existing instruments by more than one order of magnitude. "Solar Physics and Space Weather with LOFAR" is one of LOFAR's Key Science Projects. Since LOFAR covers the frequency range of 30 - 240 MHz, it is able to observe the radio radiation emitted from the outer corona of the Sun. Since radio waves are strongly scattered in the corona, the angular resolution of LOFAR radio maps will be limited to some 10s of arcseconds. The corresponding baselines include the core and the nearest remote stations. This frees the rest of the array up for obtaining dynamic radio spectra simultaneously. First solar observations with LOFAR will be presented.

Radioheliograph Observations of Solar Flares, Coronal Mass Ejections and Electron Beams

Author: Nicole Vilmer

LESIA-Paris Observatory

Co-Authors:

Presentation type: Talk

Summary:

Radio observations of the Sun provide information on the coronal structures (outside eclipses) and on their slow evolution. They also represent a very powerful tool to probe the energetic electrons produced in connection with solar activity. Radio emissions associated with solar activity can be observed in a whole frequency range from 100 GHz to a few MHz. In this talk, I shall focus on the observations in the 1 GHz-100 MHz domain (in which coherent plasma emissions are dominant) and on the contribution of spatially-resolved observations in this domain (in particular from the existing NanÃ§ay Radioheliograph). I will show on selected examples how radio emissions from electron beams propagating in the corona provide information on the electron acceleration sites and their evolution in the course of flares. Radio images also allow to investigate the development of coronal mass ejections in the low corona and to understand the relationship and connection between the energetic electrons in the corona and the ones measured in the interplanetary medium. I will show how the combination of flare HXR images with multi frequency images of radio bursts in the decimeter to dekameter wavelengths will allow to trace the magnetic connectivity between the solar surface, the corona and the interplanetary medium and I shall discuss how future ground-based solar dedicated radioheliographs and non-solar dedicated radio-interferometers will provide strong support to the future solar and interplanetary space missions.

IPS and STEREO HI - Complimentary Techniques for Observing Solar Wind Dynamics

Author: Chris Davis

RAL Space / University of Reading

Co-Authors: Richard Harrison (RAL Space), Jackie Davies (RAL Space), Steve Crothers (RAL Space), Chris Eyles (RAL Space)

Presentation type: Talk

Summary:

Interplanetary Scintillation (IPS) is a well established technique for remote sensing the speed and density of the solar wind plasma. With the advent of heliospheric imagers, most recently on the STEREO mission, it is now possible to image the same solar wind parameters from widely separated spacecraft. This talk will discuss how these complimentary techniques can combine to provide a useful insight into solar wind dynamics.

The Effect of Density Perturbations on Langmuir Waves and Electrons

Author: Heather Ratcliffe

University of Glasgow

Co-Authors: E. Kontar (University of Glasgow); N. Bian (University of Glasgow)

Presentation type: Talk

Summary:

We consider the coupling of electrons and Langmuir waves in a nonuniform plasma using weak turbulence theory. The temporal evolution of the particle spectrum is analysed in a plasma with density perturbations, using parameters applicable to the solar corona and solar wind. Assuming a Gaussian correlation function for density fluctuations and including the effects of collisions on the electrons and waves, we numerically solve the system of nonlinear kinetic equations for particles and Langmuir waves. The effects of density fluctuations on energetic electrons, and on levels of radio emission, are considered.

Slow Magnetoacoustic Oscillations in the Microwave Emission of Solar Flares

Author: Valery Nakariakov

University of Warwick

Co-Authors: S. Kim (Nobeyama Solar Radio Observatory, Japan), K. Shibasaki (Nobeyama Solar Radio Observatory, Japan)

Presentation type: Talk

Summary:

Often, variations of the microwave emission generated in solar flares by the gyrosynchrotron mechanism contain a well-pronounced oscillatory pattern, with the typical periods ranging from a few seconds to several minutes. The quasi-periodic pulsations are interpreted either in terms of MHD oscillations or auto-oscillatory regimes of the flaring plasma evolution. Analysis of the microwave data, obtained in the 17 GHz channel of the Nobeyama Radioheliograph during the C-class flare on 04/11/2010, revealed the presence of 11-min oscillations of the emitting plasma density. The oscillations decayed with the characteristic time of about 20 min. The observed properties of the oscillations are consistent with the properties of SUMER oscillations, observed in the EUV and soft X-ray bands usually as a periodic Doppler shift. The accepted interpretation of SUMER oscillations is a standing slow magnetoacoustic wave. Hence, our analysis presents the first direct observation of the slow magnetoacoustic oscillations in the microwave emission of a solar flare. In addition, the level of short-period compressible fluctuations, excited by the flare, was found to decay in time in about 25 min. The latter finding may be interpreted as the decay of flare-generated magnetoacoustic turbulence.

The Effects of Self-Indcued Electric Field on Microwave Emission in Solar Flares

Author: Valentina Zharkova

Co-Authors: N.S. Meshalkina2, L.K. Kashapova2, A.A. Kuznetsov3,2, A.T. Altyntsev2 1 Department of Mathematics, University of Bradford, Bradford BD7 1DP, UK 2 Institute of Solar-Terrestrial Physics, Siberian Branch of the Russian Academy of Sciences, P.O. Box 4026, Irkutsk 33, 664033, Russia 3 Armagh Observatory, Armagh BT61 9DG, Northern Ireland

Presentation type: Talk

Summary:

We apply the FP kinetic model of precipitation of electron beam with energy range from 12 keV to 1.2 MeV to the interpretation of X-ray and microwave emissions observed in flares. The theoretical HXR and MW emission were calculated by using the distribution functions of electron beams found by solving time-dependent Fokkerâ€“Planck approach in a converging magnetic field (Zharkova at al., 2010; Kuznetsov and Zharkova, 2010) for anisotropic scattering of beam electrons on the ambient particles in Coloumb collisions and Ohmic losses. The observed HXR photon spectra and frequency distribution of MW emission and polarization reveal the best fit for the FP models including the effect of electric field induced by beam electrons precipitating in a converging magnetic loop. The observed HXR energy spectrum is shown to be a double power law which was fit precisely by the photon spectrum simulated for the models including the self-induced electric field. The MW emission simulated for different models was fit to the observed distribution in frequency revealing that only the models combining collisions and electric field effects with pitch angle anisotropy were able to reproduce closely the main features of the observed MW emission: peak frequency, a smooth decrease of MW emission towards lower frequencies and the correct frequency of the MW polarization reversal. MW emission spectra (1â€“80 GHz) and polarization in the flares 10 March 2001 and 23 July 2002 are fit by these model simulations.

Exploring a Solar Flare Acceleration Region Using Radio and X-Ray Data

Author: Hamish S. Reid

LESIA-Paris Observatory

Co-Authors: N. Vilmer (LESIA- Paris Observatory); E.P. Kontar (University of Glasgow)

Presentation type: Talk

Summary:

We estimate the properties of a solar flare acceleration region using the simultaneous analysis of radio type III and hard X-ray data. With the Nancay radioheliograph and Phoenix 2 for radio observations and RHESSI for hard X-ray observations we investigate the outward propagation of an accelerated electron beam. We find an anti-correlation between the hard X-ray spectral index and the starting frequency of the type III radio burst. Through both an analytical model and using numerical simulations, we show that the starting height of the type III emission is heavily dependent upon the initial electron beam spectral index and acceleration region size. We then use all this information together to estimate the height and vertical extent of the solar flare acceleration region finding values of 50 Mm and 10 Mm respectively. The high coronal acceleration region found in this study agrees with previous observational predictions from electron time-of-flight analysis.

Discovery of Carbon Monoxide in the Upper Atmosphere of Pluto

Author: Jane Greaves

University of St Andrews

Co-Authors: Ch. Helling (University of St Andrews); P. Friberg (Joint Astronomy Centre)

Presentation type: Talk

Summary:

Only one molecule, methane, has ever been detected in Pluto's thin and fragile atmosphere. Carbon monoxide is also expected, sourced from evaporation of surface ice, and acting as the key coolant. Using the JCMT in 2009/10, we detected the millimetre-wave CO 2-1 rotational transition, at a brightness requiring that the gas extends into the cold upper atmosphere, as high as three Pluto radii above the surface. Compared to an upper limit from 2000, the line-centre signal is at least twice as bright. This implies the atmosphere has significantly altered in composition or size over only a decade, in a striking example of extraterrestrial climate change.

Radio Remote-Sensing Studies of the Inner Heliosphere

Author: Mario M. Bisi

Institute of Mathematics and Physics, Aberystwyth University

Co-Authors: R.A. Fallows (Institute of Mathematics and Physics, Aberystwyth University), A.R. Breen (Institute of Mathematics and Physics, Aberystwyth University), E.A. Jensen (ACS Consulting, Houston), J.M. Clover (Center for Astrophysics and Space Sciences, University of California, San Diego), P.K. Manoharan (Radio Astronomy Centre, National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Ooty), B.V. Jackson (Center for Astrophysics and Space Sciences, University of California, San Diego), P.P. Hick (Center for Astrophysics and Space Sciences/San Diego Supercomputer Center, University of California, San Diego), J.A. Davies (STFC Rutherford Appleton Laboratory), M.J. Owens (Space Environment Physics Group, Department of Meteorology, University of Reading), and S. Hardwick (Institute of Mathematics and Physics, Aberystwyth University).

Presentation type: Poster

Summary:

Radio remote-sensing observations of the inner heliosphere can be undertaken by both the observation of interplanetary scintillation (IPS) of astronomical radio sources and also the observation of Faraday rotation (FR) of spacecraft or astronomical radio sources. The data sets from various IPS-capable systems are used with the University of California, San Diego (UCSD) three-dimensional (3-D) tomographic-reconstruction and visualisation algorithms. We are able to make comparisons with multi-point it in-situ measurements from various deep-space spacecraft using our reconstruction results. This makes possible the study of structure in the inner heliosphere as a whole as well as the ability to isolate individual features or events such as interplanetary coronal mass ejections (ICMEs) or stream interaction regions (SIRs). FR is the rotation that occurs as an electromagnetic wave traverses a birefringent medium such as the solar corona and inner heliosphere. FR is the integrated product of the electron density and the component of the solar magnetic field parallel to the wave vector of the electromagnetic wave. We will present and discuss the most-recent radio remote-sensing observations of the inner heliosphere using the newly-operational LOw Frequency ARray (LOFAR) as well as those results from other radio-capable systems. We will also investigate the global structure of the heliosphere during the current and previous solar minima using radio-based data primarily, and discuss similarities and differences between the two solar cycles where possible.

Saturnâ€™s Radio Emissions and their Relation to Magnetospheric Dynamics

Author: Caitriona Jackman

University College London

Co-Authors: L. Lamy (LESIA, Meudon), P. Zarka (LESIA, Meudon), B.Cecconi (LESIA, Meudon), W.S. Kurth (Univ. of Iowa), M.P. Freeman (BAS), S.W.H. Cowley (Univ. of Leicester), and M.K. Dougherty (Imperial College London)

Presentation type: Poster

Summary:

With the arrival of the Cassini spacecraft at Saturn in July 2004, there have been quasi-continuous observations of Saturn Kilometric Radiation (SKR) emissions. We begin by reviewing solar wind data upstream of Saturn and discuss the link between solar wind compressions and dynamics in Saturn's magnetosphere, evidenced by intensifications and occasional phase changes in the SKR emission. We then review the link between magnetotail reconnection and planetary radio emissions. We begin in the well-sampled magnetotail of Earth and then move to Saturn where exploration of the nightside magnetosphere has revealed evidence of plasmoid-like magnetic structures and other phenomena indicative of magnetotail reconnection. In general, there is a good correlation between the timing of reconnection events and enhancements in the SKR emission, coupled with extension of the emission to lower frequencies. We interpret this as growth of the radio source region to higher altitudes along the field lines, stimulated by increased precipitation of energetic electrons into the auroral zones following reconnection. We also comment on the observation that the majority of reconnection events occur at SKR phases where the SKR power would be expected to be rising with time, indicating that reconnection is most likely to occur at a preferred phase. We conclude with a summary of the current knowledge of the link between Saturn's magnetospheric dynamics and SKR emissions, and list a number of open questions for the future.

Long term trends in solar activity and the heliosphere

Author: R. J. Forsyth

Imperial College London

Co-Authors: M. Lockwood (University of Reading)

Session: SOL: The rise of Solar Cycle 24 and its implications for space weather

Presentation type: Talk

Summary:

The solar minimum at the end of cycle 23 was characterised by unusually low values of many solar and heliospheric parameters when viewed on the timescale of the space age since the 1960s. For example, this minimum was an unusually extended and deep one in terms of sunspot numbers and spotless days. In the heliosphere, both the magnetic flux and solar wind dynamic pressure were the lowest since records began likely leading to a reduction in the size of the heliosphere and a greater influx of cosmic rays. Yet viewed over a much longer timescale of the order of 100 years the recent low solar activity appears not so unusual and could be described as coming to the end of an extended "grand maximum" of activity. We will review these past trends in solar activity and consider the implications for cycle 24 and the consequences in the heliosphere.

SMART-ASAP: A New Flares Prediction System for Solar Cycle 24

Author: R. Qahwaji

Co-Authors: O. Ahmed1, T. Colak1, P. Higgins2, P. Gallagher2 and S. Bloomfield2 1 University of Bradford, UK 2 Trinity College Dublin, Ireland

Session: SOL: The rise of Solar Cycle 24 and its implications for space weather

Presentation type: Talk

Summary:

In this work, recent advances in solar physics are integrated with recent advances in solar imaging, machine learning and feature selection to study the feasibility of developing the next-generation of automated flares prediction technology, which could be operational during Solar Cycle 24. Novel technologies are developed to study the flare prediction capability of magnetic feature (MF) properties generated by the recently developed Solar Monitor Active Region Tracker (SMART) and to identify the SMART's MF properties that are most significantly related to flares. Spatio-temporal association algorithms are developed to associate MFs with flares from April 1996 to December 2010. Machine-learning algorithm is applied to the associated datasets to determine the flare prediction capability of the SMART MF properties. The prediction performance is assessed using standard forecast verification measures and compared with the prediction measures of one of the industry's standard technologies, which is the Automated Solar Activity Prediction system (ASAP). The comparison shows that the new SMART-ASAP system has the potential to achieve more reliable flare prediction than ASAP.

The response of the solar interior to the unusual solar activity cycle

Author: Yvonne Elsworth

University of Birmingham

Co-Authors: Bill Chaplin (University of Birmingham) Anne-Marie Broomhall (University of Birmingham)

Session: SOL: The rise of Solar Cycle 24 and its implications for space weather

Presentation type: Talk

Summary:

Seismic observations of the interior of the Sun have been conducted by BiSON for the last three activity cycles. These data give us a unique window inside the Sun, through its convection zone and the tachocline which is believed to be the seat of the large scale dynamo action and in to the energy-generating core. We see that the natural oscillation frequencies of the Sun are influenced by the surface activity cycle. We will discuss the reasons why the location of the seismic changes is understood to be very close to the surface. Recently, it has become clear that there is variability on shorter timescales of about two years which are slightly deeper seated and may possibly be indicative of other dynamo action. These variations have been particularly prominant in the recent extended minimum.

Space Weather Precursor Services under ESA

Author: Gareth Lawrence

RHEA System SA

Co-Authors: Simon Reid (RHEA System); Eva Robbrecht (Royal Observatory of Belgium); Michel Kruglanski (Belgian Institute of Space Aeronomy); Rowena Smillie (SpaceBel) Norbert Jakowski (German Aerospace Agency); Daniel Heynderickx (DH Consultancy); Pablo Beltrami (Etamax); Truls-Lynne Hansen (University of Tromso)

Session: SOL: The rise of Solar Cycle 24 and its implications for space weather

Presentation type: Talk

Summary:

The contract SN-1 Space Weather Precursor Services (Part 1) is one of the first contracts to be awarded by ESA under the Space Weather element of the Space Situational Awareness (SSA) programme. The project has two primary objectives: a) develop roadmaps and requirements for a future set of SSA Space Weather services, and b) deploy existing topical key assets to provide initial Space Weather services with a Service-Oriented approach. The overall service topology of both the Space Weather element and SSA programme will be described, and we will elaborate on key concepts like: Federated Elements, Expert Groups, User Domains and Expert Users and illustrate the relationships and dependencies between them. It is important to note that the scientific community is anticipated to be an End User of SSA services from the earliest stages, and one of the User Domains is clearly aimed at scientists. We will underline the important role that the scientific community has to play in the evolution of the project, and show how this input may influence the future Space Weather services provided under the SSA programme.

Author: Giulio Del Zanna

University of Cambridge

Co-Authors: V.Andretta (INAF, Italy)

Session: SOL: The rise of Solar Cycle 24 and its implications for space weather

Presentation type: Talk

Summary:

We present extreme-ultraviolet (EUV) irradiances of the Sun taken during the 1998--2010 period from SOHO CDS NIS, the first set of EUV spectral observations spanning a solar cycle. The irradiances are compared to SDO/EVE measurements. Lines produced in different ways in the solar corona show marked differences in their variability. For lines formed around 1--3 MK, and to a less extent, the helium lines, we find a good linear correlation between CDS irradiances and the 10.7 cm radio flux, although each line has a different coefficient. No correlation is found for the transition-region lines. Significant discrepancies between the observed irradiances and those modelled is found.

A Novel New Radar Technique to Study Geomagnetic Storms: Superposed Latitude-Velocity-Time Plots

Author: James Hutchinson

University of Leicester

Co-Authors: D. M. Wright (University of Leicester); S. E. Milan (University of Leicester); A. Grocott (University of Leicester)

Session: SOL: The rise of Solar Cycle 24 and its implications for space weather

Presentation type: Poster

Summary:

Geomagnetic storms cause large global disturbances in the Earthâ€™s magnetosphere, during which large amounts of energy are deposited in the magnetotail and inner magnetosphere, producing an enhanced ring current and energising plasma to relativistic levels by little-known excitation mechanisms. As we approach more active times in solar cycle 24, understanding and predicting the effects of space weather will be crucial in protecting both space and terrestrial based applications such as GPS and national power grids. By exploiting data from the Advanced Composition Explorer (ACE) spacecraft in conjunction with space- and ground-based measurements of geospace over the last solar cycle, a superposed epoch analysis of 143 geomagnetic storms has been completed. Using a superposition method based on average periods of storm phases rather than a simple t0 alignment, it was found that there is a dual trend seen in the main phase duration with storm size, given by maximum negative excursion of SYM-H, contrary to previous studies results. This study makes use of radar backscatter observed by the Super Dual Auroral Radar Network (SuperDARN) and auroral imagery from the IMAGE and POLAR spacecraft missions to better constrain the storm time coupling between the solar wind and magnetosphere and to develop storm phase trends previously identified. We present initial findings of a new radar technique using line of sight, latitude-velocity-time plots analogous to standard RTI plots but using ionospheric convection maps to allow better superposition by removing temporal/spatial problems of moving radars. These, along with cross-cap potential data derived from map potential data, are compared to superposed auroral keograms and the geomagnetic and SW data from our previous study. Initial findings show that the cross cap potential increases during storm main phase and confirm the oval radius - ring current relationship identified by Milan et al., 2009.

Large-Scale Zonal flows during the Solar Minimum and the Rise of Cycle 24

Author: Rachel Howe

Co-Authors: R.W.Komm (National Solar Observatory); F.Hill (National Solar Observatory); J.Christensen-Dalsgaard (Aarhus University); T.P.Larson (Stanford University); J.Schou (Stanford University); M.J.Thompson (High Altitude Observatory/University of Sheffield)

Session: SOL: The rise of Solar Cycle 24 and its implications for space weather

Presentation type: Poster

Summary:

The so-called torsional oscillation is a pattern of migrating zonal flow bands that move from mid-latitudes towards the equator and poles as the magnetic cycle progresses. Helioseismology allows us to probe these flows below the solar surface. The prolonged solar minimum following Cycle 23 was accompanied by a delay of 1.5 to 2 years in the migration of bands of faster rotation towards the equator. During the rising phase of Cycle 24, while the lower-level bands match those seen in the rising phase of Cycle 23, the rotation rate at middle and higher latitudes remains slower than it was at the corresponding phase in earlier cycles, perhaps reflecting the weakness of the polar fields. We will present the latest results based on nearly sixteen years of global helioseismic observations from the Global Oscillation Network Group (GONG) and the Michelson Doppler Imager (MDI) and discuss the implications for the development of Cycle 25.

Two off-phase dynamo waves detected with the PCA analysis of the background and sunspot magnetic fie

Author: Prof. Valentina Zharkova

Co-Authors: Zharkova V.V., Popova H. and Zharkov S.I.

Session: SOL: The rise of Solar Cycle 24 and its implications for space weather

Presentation type: Poster

Summary:

The variations in latitude and time of the solar background and sunspot magnetic fields in the cycle 21-23 are analyzed with the Principle Component Analysis technique. We identified the two main latitude periodical components of the opposite polarities reflecting two primary waves of the background magnetic field in each hemisphere travelling off-phase. We built the latitudinal distribution for these waves and study the phase relations between the weak background solar magnetic (poloidal) field and strong magnetic field associated with sunspots (toroidal) field. In the attempt to interpret the outcome of PCA analysis, some preliminary model simulations are carried out for the modified Parkerâ€™s dynamo theory for few regimes. The outcome is discussed in relation to a weaker solar activity in the cycle 24.

Bayesian inference in astronomy

Author: Dr Martin Hendry

University of Glasgow

Co-Authors:

Session: STA: Recent developments in astrostatistics

Presentation type: Talk

Summary:

The application of advanced statistical methods to the analysis of astronomical data has a long history, and indeed played an important role in the historical development of statistics. In recent years there has been a huge growth in the application of Bayesian inference methods across many fields - from solar physics to cosmology and gravitational wave astronomy. In many cases these astronomical applications have again been driving progress and development in the methodology itself. In this talk I will review the basic principles of Bayesian inference and highlight a selection of current topics in which the very latest Bayesian methods are being applied in astronomy.

Towards a Bayesian interpretation of microwave background anomalies

Author: Dr Andrew Pontzen

Institute of Astronomy, Cambridge

Co-Authors: Hiranya Peiris (UCL)

Session: STA: Recent developments in astrostatistics

Presentation type: Talk

Summary:

I will outline how a posteriori frequentist statistics can give a misleading impression of any single realisation of an underlying distribution. As an example I will summarize a recent line of work (arXiv:1004.2706) looking at the significance of one particular anomaly in the CMB, that of the 'vanishing angular correlation function' on large scales on the masked sky. Frequentist analysis suggests this anomaly is highly statistically significant. However the result on the cut-sky can straight-forwardly be linked to properties of the full sky; from there one may further show, using Bayesian statistics, that the result is unlikely to have cosmological significance. This illustrates the dangers of taking frequentist P-values at face value. I will also comment on the controversy over reconstructing the CMB temperature field on the full sky from cut sky data (e.g. Copi et al 1009.5880; Aurich & Lustig 2010, MNRAS).

The use of topographic mapping in visualisation and classification: application to light curves

Author: Somak Raychaudhury

School of Physics and Astronomy, University of Birmingham

Co-Authors: Peter Tino (School of Computer Science, University of Birmingham) Nikolaos Gianniotis (Department of Geosciences, University of Postdam)

Session: STA: Recent developments in astrostatistics

Presentation type: Talk

Summary:

We present a probabilistic generative approach for constructing topographic maps of high-dimensional multivariate astronomical datasets. This formalism defines a low-dimensional manifold of models, resulting from a smooth non-linear mapping from a low-dimensional latent space to the space of probabilistic models of the observed data. The use of a training set helps to project each vector to a point in the latent space, obtained from the mean of posterior probabilities over the local noise models, given the data. The smooth nature of the mapping between the latent space and the model manifold enables us to analytically calculate magnification factors that reveal local contractions or expansions in the projections, resulting from the non-linearity in the topographic mapping. As an application of this general approach, we apply it to samples of artificially generated and real light curves of eclipsing binaries, and show that this is an efficient way of searching for transiting extrasolar planets in large datasets.

Zonal Modes of CMB Temperature Maps

Author: Jo Short

Cardiff University

Co-Authors: P. Coles (Cardiff University)

Session: STA: Recent developments in astrostatistics

Presentation type: Poster

Summary:

The angular part of the Fourier decomposition in spherical coordinates involve functions known as spherical harmonics. They are frequently used in astronomy for example when looking at the cosmic microwave background (CMB). Spherical harmonic decomposition involves modes labeled by their degree â„“ and order m; individual combinations of these modes generate patchwork patterns over an all-sky map. A special case of these are known zonal modes, i.e when m = 0, and these generate a sky pattern that varies only with latitude. This is of particular interest for the CMB since the zonal modes will align with the galactic plane; any anomalous behavior in them might therefore be an indication of erroneous foreground substraction. In this work we performed a simple statistical analysis of the modes with low â„“ for all sky CMB maps derived via different cleaning procedures from the Wilkinson Microwave Anisotropy Probe (WMAP), and show that the zonal modes provide a useful diagnostic of possible systematics.

Comparing the topology of force-free fields

Author: Stephane Regnier

University of Central Lancashire

Co-Authors:

Session: TOP: Topology of solar & stellar magnetic fields

Presentation type: Talk

Summary:

In the last decades, lots of magnetic field studies have shown the importance during solar eruptions of topological elements such as null points, separatrix surfaces and separators. For instance, the Bastille Day flare observed in 1998 has been related to the existence of a spine-fan structure within a potential field configuration (Aulanier et al. 2000, ApJ, 540, 1126). In order to derive the 3D magnetic field topology, force-free models are used assuming that the observed region is in an equilibrium state structured by the magnetic forces. Several assumptions are often considered: potential, linear and non-linear force-free fields. We design a study of these different assumptions to answer the following question: do they have the same magnetic topology? Providing a distribution of the magnetic field on the surface, we analysis the differences and similarities of the different magnetic field configurations in terms of magnetic energy, connectivity of field lines, distribution of electric currents and the stability of a null point. We conclude that, for a reasonable distribution of the force-free parameter, the topology stays the same for one model to the other, especially the location and strength of a null point remain the same. We finally discuss the implications for the future of magnetic field extrapolation models.

A Non-Linear Force-Free Field Model for the Solar Magnetic Carpet

Author: Karen Meyer

University of St Andrews

Co-Authors: D. H. Mackay (University of St Andrews); A. A. van Ballegooijen (Harvard-Smithsonian Center for Astrophysics)

Session: TOP: Topology of solar & stellar magnetic fields

Presentation type: Talk

Summary:

We present a new 2D model for the photospheric evolution of the solar magnetic carpet, that reproduces many observational parameters. The basic evolution of magnetic elements within the model is governed by a supergranular flow profile. In addition, magnetic elements may evolve through the processes of emergence, cancellation, coalescence and fragmentation. The synthetic magnetograms produced by the 2D model are used as photospheric boundary data to drive the continuous evolution of a 3D non-linear force-free coronal field. The coronal evolution technique will also be applied to real magnetogram data from SDO/HMI.

Modelling the Impact of Star Spots on Stellar Light Curves

Author: Robert Kidd

Lancaster University

Co-Authors: J.A.Wild(Lancaster University)

Session: TOP: Topology of solar & stellar magnetic fields

Presentation type: Talk

Summary:

Spots are a proxy of solar or stellar activity and may indicate the likely severity of the space weather environment within the star system. The analysis of spots on stars similar to the Sun will place the Sunâ€™s activity in a wider context and allow conclusions to be drawn on possible extremes of future Solar activity. To this end we present a model designed to predict the light curves for realistic spot configurations on various parent stars. The model exploits the decrease in the stars brightness as the visibly darker spot moves across the face of the star in order to simulate the overall variations in magnitude. Results from this model will be presented and the feasibility of detecting star spots within current detectors discussed.

Mad, bad and dangerous to know: prominences and flares on young stars.

Author: Joe Llama

University of St Andrews

Co-Authors: M.M. Jardine (University of St Andrews), A.N. Aarnio (University of Michigan)

Session: TOP: Topology of solar & stellar magnetic fields

Presentation type: Talk

Summary:

Large magnetic structures such as prominences and flaring loops are now well observed and understood on the Sun. On younger more active stars analogues to these structures have been observed on far greater length scales than on the Sun. Indeed, stellar prominences and flaring loops have been observed extending many stellar radii above the surface of the star and the nature of their confinement is still a matter for debate. The height and relative size of these structures makes them of great importance to young stars as the rotational evolution of the star is largely governed by the magnetic interaction between the star and its disk in the early stages and through the stellar wind and coronal mass ejections at later stages. Both of these processes are highly dependent on the sizes of the loops. We have modelled the mechanical support of large prominences and also flaring loops that form within the stellar wind of young stars. We find they can be supported well beyond the expected extent of the X-ray bright corona. The loss of this equilibrium may result in both mass and angular momentum being lost from the star in the stellar equivalent of a Coronal Mass Ejection. This could have devastating consequences for planetary magnetospheres and the planetary environment.

MHD Evolution of X-points to MHS Equilibria

Author: Jorge Fuentes Fernandez

University of St Andrews

Co-Authors: C. E. Parnell, A. W. Hood (University of St Andrews)

Session: TOP: Topology of solar & stellar magnetic fields

Presentation type: Talk

Summary:

Magnetic reconnection is a key process on the Sun which is important for coronal heating, producing flares and driving the solar wind. Current layers are a key requirement for reconnection, however little is know about their formation and characteristics in the presence of a plasma pressure which will naturally be important at null points where the magnetic field is zero. We present a numerical study of the effects of plasma pressure on the collapse of 2D magnetic X-points. Unlike previous studies, which use a simple relaxation code, we consider the non-resistive MHD evolution to a current sheet, using real viscous damping forces. This enables us to determine the energetic consequences (such as heating) from the collapse. We show that the system is trying to collapse to a current singularity at the location of the null. However, the presence of a plasma pressure reduces the growth rate of the singularity to such an extent that in reality it is unachievable. We provide an analytical description of the system in a quasi-static equilibrium at a given time, in which a finite current layer has formed at the null. The dynamical evolution of the system and the dependence of the final state on the initial plasma and magnetic quantities is discussed as are the energetic consequences.

Coronal mass ejection-flare relationship and the topology of the erupting field

Author: Bernhard Kliem

UCL, MSSL

Co-Authors: T. Toeroek (PSI, San Diego, CA, USA); T. G. Forbes (UNH, Durham, NH, USA)

Session: TOP: Topology of solar & stellar magnetic fields

Presentation type: Talk

Summary:

Observations of coronal mass ejections (CMEs) and solar flares often show a correlation between the acceleration of the ejecta and the plasma heating and particle acceleration signified by the soft and hard X-ray emissions of the associated flare (the latter are thought to result from magnetic reconnection). This finding has stimulated the discussion of the CME-flare relationship, but at the same time it has made it difficult to find a conclusive answer as to whether an ideal MHD instability or magnetic reconnection is the prime cause of the eruptions. Numerical simulations of unstable flux ropes will be presented which successfully model CMEs. Some of these show a high degree of synchronization between the initial exponential acceleration of the flux rope, due to the ideal MHD instability, and the rise of reconnection. However, in others the reconnection sets in with a delay which can extend up to the phase after the flux rope's acceleration peak. In addition, the reconnection flows generally lag behind the motions driven by the ideal instability when the flux rope rise velocity nears the saturation phase. These properties suggest that the ideal MHD process is the primary driver of the coupled CME-flare phenomenon. The strong differences in the degree of synchronization are related to the magnetic topology prior to the eruption. Observations of CME vs. flare timing thus allow to infer which of the two basic flux rope topologies is relevant.

Current sheet formation and heating

Author: Ruth Bowness

University of St Andrews

Co-Authors: A. W. Hood (University of St Andrews); C. E. Parnell (University of St Andrews)

Session: TOP: Topology of solar & stellar magnetic fields

Presentation type: Poster

Summary:

Solar photospheric footpoint motions can produce strong, localised currents in the corona. A detailed understanding of the formation process and the resulting heating is important in modelling nanoflares, as a mechanism for heating the solar corona. A 3D MHD simulation is described in which an initially straight magnetic field is sheared in two directions with grid resolutions up to $512^3$. A twisted current layer is formed which reduces in width and increases in maximum current as the grid is refined. This, together with the residual Lorentz forces calculated, suggest that a current sheet is trying to form. Realistic coronal temperatures are obtained.

The Topology of Flux Emergence and its Observational Consequences

Author: Clare Parnell

University of St Andrews

Co-Authors: Parnell, C.E., Haynes, A.L. and Maclean, R.C.

Session: TOP: Topology of solar & stellar magnetic fields

Presentation type: Poster

Summary:

Flux emergence is a common, wide spread process on the Sun which injects some 10^25 Mx of flux per day into the solar atmosphere. It is known to be a key source of heat for the solar corona and is often associated with flaring and dynamic activity in the solar atmosphere. Using numerical resistive 3D MHD models of flux emergence, we determine the separatrix surfaces and numerous separators found at the interface between the emerging flux tube and overlying coronal field. By comparing these topological structures to the main signatures of 3D reconnection, such as the integrated parallel electric field along fieldlines, we demonstrate that the magnetic skeleton is central to understanding the nature of the reconnection mechanism in flux emergence (Parnell, Maclean and Haynes, Astrophys. J. Lett. 725, 2010). Furthermore, we look at the behaviour of the plasma as a consequences of this reconnection and show how flux emergence leads to the broad heating of many field lines, and possible flaring, which naturally arises from flux emergence.

The disappearance of a prominence

Author: Owen Roberts

Aberystwyth University

Co-Authors: Xing Li(Aberystwyth University)

Session: TOP: Topology of solar & stellar magnetic fields

Presentation type: Poster

Summary:

Using high cadence data from the STEREO B EUVI telescope in the He II 304Ã… line, the disappearing of a prominence above the north west limb is observed between 00:00UT May 9th and 07:00 May 10th 2007. During this prolonged period of activity various motions of material are observed. Under the assumption that that what is observed is cool plasma, the motions are best described as the coronal rain often reported in the literature. This is a reasonable assumption since the 304Ã… bandpass is dominated by the cool (~10,000K) He II line and the contribution of the hotter Si IX is small in comparison. Further support is that the motions are absent in other EUVI hot lines such as 195 Ã…. The motions of the cool plasma appear to initiate from the prominence and fall down to the solar surface along complex magnetic field lines. This includes an instance of material distributed at different heights initially travelling in a parallel manner but eventually falling into the same footpoint. The prominence therefore is a region of concentrated magnetic flux. The prominence becomes thinner and eventually disappears after all the cool plasma falls back to the solar surface along magnetic loops.

What's going on in that flux tube?

Author: Anthony Yeates

University of Dundee

Co-Authors: G.Hornig (University of Dundee)

Session: TOP: Topology of solar & stellar magnetic fields

Presentation type: Poster

Summary:

Magnetic loops in solar and stellar coronae are but one example of evolving magnetic flux tubes. Mathematically, a flux tube at a given time snapshot corresponds to a dynamical system, with magnetic field lines corresponding to particle trajectories. This analogy opens up a number of mathematical techniques and ideas that can be exploited to characterise the structure and dynamics of 3D magnetic fields. For example, we can pin down what is meant by complexity of a magnetic field, and quantify how complex a magnetic structure to expect from different photospheric motions. Another exciting area is our recent identification of topological properties that constrain possible evolutions of magnetic loops, including both turbulent and/or resistive dynamics.

Periodic spectral line asymmetries in solar coronal structures from slow magnetoacoustic waves

Author: Erwin Verwichte

University of Warwick

Co-Authors: M.Marsh (University of Central Lancashire); C.Foullon (University of Warwick); T.Van Doorsselaere (Katholieke Universiteit Leuven, Belgium); I.De Moortel (University of St Andrews); A.W.Hood (University of St Andrews); V.M. Nakariakov (University of Warwick)

Session: UKSP: UKSP General session

Presentation type: Talk

Summary:

Recent spectral observations of upward moving quasi-periodic intensity perturbations in solar coronal structures have shown evidence of periodic line asymmetries near their footpoints. These observations challenge the established interpretation of the intensity perturbations in terms of propagating slow magnetoacoustic waves. We show that slow waves inherently have a bias toward enhancement of emission in the blue wing of the emission line due to in-phase behavior of velocity and density perturbations. We demonstrate that slow waves cause line asymmetries when the emission line is averaged over an oscillation period or when a quasi-static plasma component in the line of sight is included. Therefore, we conclude that slow magnetoacoustic waves remain a valid explanation for the observed quasi-periodic intensity perturbations.

Rapid Oscillations in the Solar Atmosphere (ROSA); the instrument and some recent results

Author: Gareth Dorrian

Queens University Belfast

Co-Authors: D. Jess (Queen's University Belfast); M.Mathioudakis (Queen's University Belfast); D. Christian (California State University Northridge)

Session: UKSP: UKSP General session

Presentation type: Talk

Summary:

Rapid Oscillations in the Solar Atmosphere (ROSA) is a high-cadence, high-resolution imager of the photosphere and chromosphere. The instrument comprises six cameras which are synchronized to take simultaneous images of the low solar atmosphere at multiple wavelengths. The system is available on the Dunn Solar Telescope at the National Solar Observatory, at Sacramento Peak, New Mexico. This talk will include a summary description of the instrument operation and imaging capabilities and a review of some recent results.

Heating of solar chromosphere by electromagnetic wave absorption in a plasma slab model

Author: Roman Pechhacker

Queen Mary University of London

Co-Authors: D.Tsiklauri (Queen Mary University of London); R.Pechhacker (Queen Mary University of London)

Session: UKSP: UKSP General session

Presentation type: Talk

Summary:

The heating of chromospheric inter-network regions by means of the absorption of electromagnetic (EM) waves that originate from the photospheric blackbody radiation is studied in the framework of a plasma slab model. The absorption is provided by the electron-neutral collisions. Given the uncertain nature of the collision cross-section due to the plasma micro-turbulence, it is shown that for plausible physical parameters, the heating flux produced by the absorption of EM waves in the chromosphere is between 20% and 45% of the chromospheric radiative loss flux requirement. It is also established that there is an optimal value for the collision cross-section, 5*10^(18) m^2, that produces the maximal heating flux of 1990 W/m^2.

The Hot Corona and the Significance of Magnetic Field Instability

Author: Michael Bareford

Jodrell Bank Centre for Astrophysics

Co-Authors: P.K.Browning (Jodrell Bank Centre for Astrophysics); R.A.M.Van der Linden (Royal Observatory of Belgium)

Session: UKSP: UKSP General session

Presentation type: Talk

Summary:

The million degree temperature of the corona might be due to the combined effect of barely-distinguishable energy releases, so-called nanoflares, that occur throughout the solar atmosphere. We investigate the plausibility of the nanoflare heating by constructing a magnetohydrodynamic model that can derive the energy of nanoflares, based on the hypothesis that the ideal kink instability of a twisted loop triggers a relaxation to a minimum energy state. The energy release depends on the current profile when the ideal kink instability threshold is crossed. Subsequent to instability onset, fast magnetic reconnection ensues in the nonlinear phase. As the flare erupts and declines, the field transitions to a lower energy, which can be modelled as a helicity-conserving relaxation to a linear force-free state. Results of 3D numerical MHD simulations of unstable loops are presented, showing the dynamics of the relaxation process. We apply our model to ensembles of loops driven by random photospheric twisting motions. By making adjustments to loop size and ensemble behaviour we obtain a set of flare energy distributions, from which a range of active-region heat fluxes is determined. The power-laws derived from these distributions are at or above the critical index.

New constraints on magnetic relaxation

Author: Anthony Yeates

University of Dundee

Co-Authors: G.Hornig, A.L.Wilmot-Smith (University of Dundee)

Session: UKSP: UKSP General session

Presentation type: Talk

Summary:

An appealing explanation for coronal heating is the gradual build-up of magnetic energy by photospheric shearing, followed by its sudden release in a turbulent â€œmagnetic relaxationâ€. While present-day numerical simulations are unable to resolve the detail of the turbulent relaxation, this may, in fact, be unimportant for predicting the total energy released. For example, experiments in various laboratory devices bear out Taylorâ€™s hypothesis: knowing the total magnetic helicity (and magnetic flux) of the initial state is sufficient to predict the final, relaxed state. But the question remains open whether the total helicity is the only constraint on relaxation in astrophysical situations like the solar corona. In particular, recent numerical simulations of relaxing coronal loops find that the predicted Taylor state is not always reached, despite conservation of helicity. I will describe how we have resolved this discrepancy, uncovering in the process a new kind of constraint on the magnetic relaxation.

A Family of One-Dimensional Vlasov-Maxwell Equilibria for the Force-Free Harris Sheet

Author: Fiona Wilson

University of St Andrews

Co-Authors: T. Neukirch (University of St Andrews)

Session: UKSP: UKSP General session

Presentation type: Talk

Summary:

A family of self-consistent collisionless distribution functions for the force-free Harris sheet is presented. This family includes the distribution function recently found by Harrison and Neukirch [Phys. Rev. Lett. 102, 135003 (2009)] as well as distribution functions with a different dependence on the particle energy, but with the same dependence on the canonical momenta. It is shown generally that the other distribution functions in the family give rise to the same pressure function and thus to the same current density as the known distribution function, provided certain conditions on the parameters are satisfied. A number of examples of distribution functions from the new family are given.

Stochastic Particle Transport In The Presence of Magnetic Fields

Author: Christina Burge

University of Glasgow

Co-Authors: A. L. Mackinnon P. Petkaki

Session: UKSP: UKSP General session

Presentation type: Talk

Summary:

The X-type neutral point has long been used as a simple model to describe the post-reconnection topology of acceleration regions in the corona. To make such a model more realistic, we introduce turbulence via a superposition of wave mode oscillations in the magnetic and electric fields, and conduct test particle simulations to integrate the orbits of particles in the presence of such fields. A method to incorporate pitch angle scattering by integrating these orbits stochastically has also been developed. Such a stochastic integrator can also be used to model cross-field scattering.

Observations of rotating sunspots from the Solar Dynamics Observatory

Author: Daniel Brown

University of Central Lancashire

Co-Authors:

Session: UKSP: UKSP General session

Presentation type: Talk

Summary:

The torsional rotation of sunspots about their umbra centres has previously been observed in continuum data by space- and ground-based observatories. These rotations have typical speeds of a couple of degrees per hour, so several days of continuous, high-resolution observations are required to observe a useful proportion of a sunspot rotation. The Helioseismic and Magnetic Imager (HMI) on NASA's Solar Dynamics Observatory (SDO) now provides suitable data sets for studying rotating sunspots as standard. This paper will present observations of a rotating sunspot from January 2011. The sunspot was seen to change direction of rotation and travel both clockwise and anti-clockwise, consistent with a torsional oscillation. The corresponding motion of loops in the corona was seen to mirror that in the photosphere.

Evolution of sunspot magnetic fields associated with flaring

Author: Sophie Murray

Trinity College Dublin

Co-Authors: D. S. Bloomfield (Trinity College Dublin); P. T. Gallagher (Trinity College Dublin)

Session: UKSP: UKSP General session

Presentation type: Talk

Summary:

The evolution of the magnetic field in active region NOAA 10953 was examined over a period of 12 hours leading up to and after a GOES B1.0 flare. Hinode/SOT-SP Stokes profiles were inverted using the HeLIx+ Milne-Eddington code before azimuth disambiguation and transformation to the solar surface reference frame. A number of magnetic field properties and low order aspects of magnetic field topology were extracted from two flux regions that exhibited increased Ca II H emission during the flare. Pre-flare increases in vertical field strength, vertical current density and inclination angle of ~ 8degrees towards the vertical were observed in flux elements surrounding the primary sunspot. The vertical field strength and current density subsequently decreased in the post-flare state, with the inclination becoming more horizontal by ~ 7degrees. This behavior of the field vector may provide a physical basis for future flare forecasting efforts.

The rotation of the corona

Author: Huw Morgan

Institute for Astronomy, University of Hawaii

Co-Authors:

Session: UKSP: UKSP General session

Presentation type: Talk

Summary:

Solar rotational tomography is applied to 14 years of LASCO C2/SOHO observations, giving for the first time a comprehensive view of the evolution of structure throughout a whole solar activity cycle. A long-term correlation analysis is applied to the set of tomography maps, resulting in a set of rotation rates for the corona for all latitudes between -60 to 60\de\ and times between 1996-2010 at a height of 4\Rs. Rotation at the poles is erratic and often very slow. The results are interpreted in terms of the various magnetic features (active regions, filaments) which lie at the footpoints of the coronal streamers, and the relative latitudinal configuration of the streamers and their footpoints throughout the activity cycle.

A Novel Refinement of the Smoothed Particle (SP) Method

Institute of Mathematics and Physics, Aberystwyth University

Co-Authors: B. PintÃ©r (Institute of Mathematics and Physics, Aberystwyth University)

Session: UKSP: UKSP General session

Presentation type: Talk

Summary:

The Smoothed Particle (SP) method is a procedure by which a set of equations that govern the dynamics of a system are approximated such that the system may be simulated numerically. Once implemented with an appropriate numerical integration, the resulting algorithms form fully Lagrangian, finite-element codes that are easy to construct and allow for the introduction of additional complex physics very simply. The algorithms also handle free-surface and periodic boundaries with no change in the algorithm itself. Each element, commonly termed a pseudo-particle, is a mobile sample point about which the macroscopic properties of the system can be interpolated. The number of pseudo-particles must be sufficiently large to reduce the errors in the approximation. There are two sources of error: the first, which cannot be known explicitly, results from the smoothing out of the value of the properties by the interpolation; and the second, E, is induced by making it discrete, which is necessitated for computation. It is this second error that is reduced by the suggested SP refinement. Herein, the nature of E has been derived explicitly, and therefore, a refinement of the SP approximations of gradient has been suggested. The act of refinement increases the accuracy to within the limit of the system, which is an unavoidable function of the smoothing error. This refinement allows for the reduction of the number of pseudo-particles and therefore the number of calculations required within a simulation. Such a method can be easily applied to many aspects of solar, heliospheric, magnetospheric, and ionospheric physics.

A new model of spin-down

Author: Eun-jin Kim

University of Sheffield

Co-Authors: Nicolas Leprovost

Session: UKSP: UKSP General session

Presentation type: Talk

Summary:

One of the outstanding problem in solar physics is to understand the evolution of magnetic fields and rotation, which play an indispensable role in the Sun and other stars. The evolution of these two is in fact inseparable since they are closely linked through spin down and dynamo processes. Specifically, magnetic fields accelerate the spin-down of stars via magnetized wind while global and differential rotation play an essential role in the generation of stellar magnetic fields (the so--called dynamo action). In this contribution, we investigate a crucial effect of intermittency in solar (stellar) winds in rotational evolution. This is a particularly important problem since there has been accumulating evidence for intermittency in solar winds, varying over a broad range of time scales. Specifically, we show that that the intermittency in solar winds plays a key role in reproducing observational data on the distribution of rotational speed as a function of ages and spectral types of stars. Furthermore, this effect is shown to be similar to dynamo saturation mechanism, which has been a popular mechanism for explaining rotational history.

Helicity transport in a simulated CME

Author: Bernhard Kliem

UCL, MSSL

Co-Authors: N. Seehafer (Univ. of Potsdam, Germany); S. Rust (Univ. of Potsdam, Germany)

Session: UKSP: UKSP General session

Presentation type: Poster

Summary:

It has been suggested that coronal mass ejections (CMEs) remove the magnetic helicity of active regions from the Sun. Such removal is often regarded to be necessary due to the hemispheric sign preference of the helicity, which inhibits a simple annihilation by reconnection between volumes of opposite chirality. We have monitored the relative magnetic helicity contained in the coronal volume of a simulated flux rope CME, as well as the upward flux of helicity through a horizontal plane in the simulation box. The unstable and erupting flux rope carries away only part of the initial helicity through the open upper boundary of the box; the larger part remains in the volume. We suggest a simple physical explanation for this result.

Passive scalar transport in sheared turbulence

Author: Dr Andrew Newton

University of Sheffield

Co-Authors: E.kim

Session: UKSP: UKSP General session

Presentation type: Poster

Summary:

The suppression of turbulent transport by large scale shear flows is demonstrated numerically by measuring the turbulent diffusion $D_t$ and scalar amplitude $\langle n'^2\rangle$ of decaying passive scalar fields $n'$ being advected by various turbulent flows. The nature of transport suppression is shown to be crucially depends on the the temporal correlation of the turbulence. Decorrelated prescribed turbulence ($\tau_c=\rightarrow 0$) is found in the strong shear limit to suppress the transport statistics with the shearing rate $\Omega$ as $D_t \propto \Omega^$, $\langle n'^2\rangle\propto\Omega^$ and $\cos\theta\propto\Omega^$. For finite correlated consistantly evolved turbulence ($\tau_c \ge \Omega^$), the scaling of the turbulence statistics with a strong shear is found to be much stronger than those for the decorrelated turbulence, with the scalings of $D_t\propto\Omega^$, $\langle n'^2 \rangle \propto\Omega^$, $\langle u_x'^2 \rangle \propto \Omega^$ and $\langle \omega'^2 \rangle \propto \Omega^$. The results from these different turbulent flows, through utilising a novel renormalisation, are shown to closely match analytical predictions [see E. Kim, Mod. Phys. Lett B , 1 (2004)] for the behaviour of $D_t$ and $\langle n'^2\rangle$. The renormalisation process provides a previously unseen insight into the underlying nature of transport suppression by stable shear flows showing how all the transport statstics are related by the turbulent diffusion.

Independent Signals from the Influence of Internal Magnetic Layers on Frequencies of Solar p-modes

Author: Claire Foullon

University of Warwick

Co-Authors: V.M. Nakariakov (University of Warwick)

Session: UKSP: UKSP General session

Presentation type: Poster

Summary:

The discovery that p-mode frequencies of low degree do not follow changes of solar surface activity during the recent solar minimum offers the possibility of a new diagnostic signature of the responsible pressure perturbation in the wave guiding medium, potentially rich of information regarding the structure of the Sun and the cause of the unusually long solar minimum. Magnetic fields, as well as temperature changes, introduce equilibrium pressure deviations that modify the resonant frequencies of p-mode oscillations. Assuming the perturbation to be caused by a horizontal layer of magnetic field located in a plane-stratified model of the Sun, we compile analytical frequency shifts and process them to allow direct comparison with observations. The effect of magnetism itself on the central p-mode frequencies can be neglected in comparison with the thermal effect of a perturbative layer buried in the solar interior. A parametric study shows that a layer as thin as 2100 km at subsurface depths is able to reproduce reported mean anomalous frequency shifts (not correlated with the surface activity), while a layer of size around 4200 km increasing by a small amount at depths near 0.08 Rsun can explain individual low-degree shifts. It is also possible to obtain the mean shifts via the upward motion through depths near 0.03 Rsun of a rising perturbative layer of thickness around 7000 km. Hence, the anomalous frequency shifts are best explained by thermal effects in the upper regions of the convection zone. The effects of latitudinal distribution are not treated here.

A large polar-crown filament eruption observed by SDO/AIA and STEREO-A/EUVI

Author: Caroline Alexander

University of Central Lancashire

Co-Authors: C. E. Alexander, S. Regnier, R. W. Walsh

Session: UKSP: UKSP General session

Presentation type: Poster

Summary:

Using the two points-of-view of SDO/AIA and STEREO-A/EUVI (about 70 degrees apart), we observed a large-scale polar crown filament eruption on 13 June 2010 in the Northern hemisphere. Comparing the plasma at 80000 K and at 0.6 MK, we deduce the structure of the filament/prominence and its evolution. The polar-crown is composed of hot and cool plasma sitting at the bottom of a cavity in upwardly concave magnetic field lines. We also study the different possible initiation processes leading to the eruption by looking at local and global events which can destabilise the filament such as weak filament activity in a nearby active region, a flare and the associated CME wave starting in the Southern hemisphere, existence of a trans-equatorial loop, instability of the filament (kink, torus, mass loading). We discuss the contribution and timing of each initiation process to the filament eruption: the mass loading scenario and the CME wave seem to be the more likely mechanisms.

Fine structure collisional data for the electron impact excitation of SIII

Author: Claire Hudson

Queen

Co-Authors: C.A. Ramsbottom (QUB); M.P. Scott (QUB)

Session: UKSP: UKSP General session

Presentation type: Poster

Summary:

Electron-ion collision processes are important in understanding the energy balance in various types of plasmas and through the use of theoretical line intensity ratios, electron temperatures, densities, and elemental abundances can be deduced. Several emission lines of S III have been observed in the ultraviolet spectra of the Sun and stellar transition regions (Doschek & Feldman 1987 ApJ 315 L67) and provide important temperature diagnostics. In order to analyse the observational data, accurate excitation collision strength values are needed. However, as reported recently by Rubin et al (2008 MNRAS 387 45) a discrepancy exists in some of the atomic data provided by the IRON Project calculation of Galavis, Mendoza & Zeippen (1995 AASS 111 347) and that of Tayal & Gupta (1999 ApJ 526 544). Therefore we have carried out a new calculation to resolve this discrepancy. Our current work utilises the recently developed parallel RMATRX II suite of codes, which performs the calculation in intermediate coupling and determines collision strengths over an electron energy range of 0-12Ryd. From these, effective collision strengths are generated for electron temperatures in the range log T(K) = 3.0 - 6.0.

Low-degree Helioseismology from the Solar Dynamics Observatory

Author: Rachel Howe

Co-Authors: A.-M. Broomhall (University of Birmingham); W.J.Chaplin (University of Birmingham); Y.P. Elsworth (University of Birmingham); F. Hill (National Solar Observatory); K. Jain (National Solar Observatory); R.W. Komm (National Solar Observatory)

Session: UKSP: UKSP General session

Presentation type: Poster

Summary:

The Atmospheric Imaging Array (AIA) aboard the Solar Dynamics Observatory (SDO) observes in several ultraviolet and extreme-ultraviolet wavelengths. The 1600 and 1700 Angstrom bands are formed in the upper photosphere and are sensitive to the five-minute oscillations used in helioseismology. We show some preliminary results from the analysis of Sun-as-a-Star time series derived from these data, and compare with results from the Helioseismic and Magnetic Imager, also aboard SDO, and the Birmingham Solar Oscillations network.

The Effect of the environment on the P1/P2 period ratio for kink oscillations of coronal loops

Author: Beniamin Orza

University of Sheffield

Co-Authors: Istvan Ballai (University of Sheffield)

Session: UKSP: UKSP General session

Presentation type: Poster

Summary:

The P1/P2 period ratio of transversal loop oscillations is currently used for the diagnostics of longitudinal structuring of coronal loops as its deviation from 2 is intrinsecaly connected to the density scale-height along coronal loops and/or the sub-resolution structure of the magnetic field. Using a straightforward variational method we show that under coronal conditions the effect of the temperature difference between the loop and the enviroment can change considerably the period ratio, this change reaching even 60%. We also show that once dispersive effects are taken account, with oscillation periods shorter than the cut-off period, the domain where the model can be applied is considerably reduced. The same technique is applied not only to coronal structures, but to other oscillating magnetic structures, e.g. prominences.

Proton velocity distribution functions of the solar wind measured by HIA/Cluster

Author: XING LI

Aberystwyth University

Co-Authors:

Session: UKSP: UKSP General session

Presentation type: Poster

Summary:

Proton velocity distribution functions (VDFs) measured by Hot Ion Analyser (HIA) instruments on board the Cluster spacecrafts in the undisturbed solar wind at 1 AU will be presented in this study. The velocity distributions functions carry important information of microscopic wave/particle interactions of the solar wind. The solar wind proton gas is essentially collisionless plasma. The proton velocity distribution functions measured at HIAâ€™s temporal resolution limit (~ 1 minute) are highly non-Maxwellian and non-gyrotropic. However, the relatively low count rates and the poor solid angle resolution of HIA may be also factors that the measured proton VDFs are non-gyrotropic. It is found that the integration of the measured velocity distributions functions over a longer time period (1-2 hours) produce VDFs that are closer to be gyrotropic, reflecting the contributions of plasma waves at various scales during the period and better statistics when more particles being counted. The measured proton VDFs frequently display elongated features along the direction of the background magnetic field. We will discuss possible interpretation of the measurements. These measurements may offer clues to the heating of the solar wind ions.

A Non-Linear Force-Free Field Model for the Solar Magnetic Carpet

Author: Karen Meyer

University of St Andrews

Co-Authors: D. H. Mackay (University of St Andrews); A. A. van Ballegooijen (Harvard-Smithsonian Center for Astrophysics)

Session: UKSP: UKSP General session

Presentation type: Poster

Summary:

Our aim is to construct a 3D non-linear force-free field model for the solar magnetic carpet. Here we present a new 2D model for the photospheric evolution of the magnetic field, that reproduces many observational parameters. The basic evolution of magnetic elements within the model is governed by a supergranular flow profile. In addition, magnetic elements may evolve through the processes of emergence, cancellation, coalescence and fragmentation. The synthetic magnetograms produced by the 2D model will be used as photospheric boundary data to drive the continuous evolution of a 3D non-linear force-free coronal field. We introduce the 3D modeling technique by first applying it to three basic small-scale magnetic interactions: emergence, cancellation and flyby.

Flare velocity shifts using the EVE spectrometer

Author: David Graham

University of Glasgow

Co-Authors: H. S. Hudson (SSL, UC Berkeley) L. Fletcher (University of Glasgow)

Session: UKSP: UKSP General session

Presentation type: Poster

Summary:

The recently launched EVE instrument on the Solar Dynamics Observatory (SDO) has given us access to high cadence uninterrupted flare observations at EUV wavelengths. Using this we present a first look at the impulsive phase of the first X-Class flare in the new solar cycle SOL2011-02-15. At high temperatures we find Fe XXIV 192.028 A to be shifted to high velocities, and with AIA imaging we attempt to observe these flows visually.

Post-main sequence evolution of low- and intermediate-mass stars: problems and challenges

Author: Maurizio Salaris

ARI - Liverpool John Moores University

Co-Authors:

Session: UNS: Unsolved problems of post-main sequence stellar evolution

Presentation type: Talk

Summary:

The post main sequence evolutionary phases of low- and intermediate-mass stars are major contributors to the photometric evolution of stellar populations with ages older than ~100 Myr, play an important role in the chemical evolution of the interstellar medium, provide a number of stellar distance indicators and additional cosmic clocks. This review will summarize the major open problems that affect RGB, HB, AGB and WD stellar evolution models, and the resulting uncertainties in some key theoretical predictions.

Solving the unsolved problems of mass loss in the winds of giant stars

Author: Iain McDonald

University of Manchester

Co-Authors:

Session: UNS: Unsolved problems of post-main sequence stellar evolution

Presentation type: Talk

Summary:

Several problems exist in explaining the origin, chemistry and driving of winds of stars on the red and asymptotic giant branches. How are these winds driven? How does pulsation affect mass loss? How does their make-up and mass-loss rate vary with metallicity? What is the mineralogical return to the ISM and how has this varied with time? I will briefly examine these problems and describe some of the steps we are making to try and answer them.

Dust Production in Giant and Supergiant Evolution

Author: Mike Edmunds

University of Cardiff

Co-Authors:

Session: UNS: Unsolved problems of post-main sequence stellar evolution

Presentation type: Talk

Summary:

Despite some 50 years of observation, theory and speculation, the relative contribution of giant and supergiant stars to the manufacture of interstellar dust remains uncertain. Yet knowledge of dust production is crucial for understanding observations of massive high-redshift galaxies. How can the uncertainties be resolved?

The Crystalline Silicate abundance arround oxygen-rich Asymptotic Giant Branch stars

Author: Olivia Jones

JBCA, University of Manchester

Co-Authors: C. Kemper (ASIAA, Taiwan); M. Min (Astronomisch Instituut Utrecht)

Session: UNS: Unsolved problems of post-main sequence stellar evolution

Presentation type: Talk

Summary:

While silicates in the ISM appear to be completely amorphous, it has been shown that the silicates in the dust shells around O-rich Asymptotic Giant Branch stars show a considerable degree of crystallinity. A threshold value for the mass-loss rate exists, above which the features due to the crystalline silicates forsterite and enstatite appear. We are investigating the origin of this threshold value by expanding the crystallinity studies to the low metallicity environments of the Magellanic Clouds. We analyse the 5-38 micron Spitzer-IRS spectra of $87$ oxygen-rich asymptotic giant branch and red supergiant stars; these evolved oxygen-rich objects encompass a range of spectral features and band strengths; from the spectrally rich which exhibit a wealth of crystalline and amorphous silicate features to the 'naked' (dust-free) stars, across a range of mass-loss rates, providing an ideal opportunity to explore the onset of crystallinity. Combining spectroscopic observations with a grid of models exploring the effects of dust composition, mass-loss rate and outer radius, we hope to trace correlations between the feature strength of crystalline silicate bands at 11.3, 23.6, 28.1, 33.6 micron, and the dust or gas density. These relations may be different at the LMC's and SMC's metallicity of ~0.5 Zsun and ~0.2 Zsun respectively. We compare our results to those for O-rich AGB stars in the Galaxy.

Carbon chemistry in Galactic Bulge Planetary Nebulae

Author: Lizette Guzman-Ramirez

JBCA, University of Manchester

Co-Authors: A. A. Zijlstra, R. Ni Chuimin, Paul M. Woods, K. Gesicki (Centrum AStronomii UMK, Poland), E. Lagadec (ESO), T. J. Millar (Queen's University Belfast)

Session: UNS: Unsolved problems of post-main sequence stellar evolution

Presentation type: Talk

Summary:

Galactic Bulge Planetary Nebulae show evidence of mixed chemistry with emission from both silicate dust and PAHs. This mixed chemistry is unlikely to be related to carbon dredge-up, as third dredge-up is not expected to occur in the low mass Bulge stars. We show that the phenomenon is widespread, and is seen in 30 nebulae out of 40 of our sample, selected on the basis of their infrared flux. HST images and UVES spectra show that the mixed chemistry is not related to the presence of emission-line stars, as it is in the Galactic disk population. We also rule out interaction with the ISM as origin of the PAHs. Instead, a strong correlation is found with morphology, and the presence of a dense torus. A chemical model is presented which shows that hydrocarbon chains can form within oxygen-rich gas through gas-phase chemical reactions. The model predicts two layers, one at Av~1.5 where small hydrocarbons form from reactions with C^+, and one at Av~4, where larger chains (and by implication, PAHs) form from reactions with neutral, atomic carbon. These reactions take place in a mini-PDR. We conclude that the mixed chemistry phenomenon occurring in the Galactic Bulge Planetary Nebulae is best explained through hydrocarbon chemistry in an UV-irradiated, dense torus.

What defines clouds in cool star winds? What happens to them in wind interactions?

Author: Anita Richards

JBCA, University of Manchester

Co-Authors: K.A. Assaf, S. Etoka, M.D. Gray (U. Manchester) I. Bains (U. Swinburne) A. Bartkiewicz, M. Szymczak (Niclaus Copernicus I., Torun) M .Elitzur (U. Kentucky) E.E. Lekht, G.M. Rudniskij (Sternberg I., LPI, Moscow) E. Mendoza-Torres (INOAE, Tonantzintla), H.J. van Langevelde (JIVE/Leiden) J.A. Yates (UCLondon)

Session: UNS: Unsolved problems of post-main sequence stellar evolution

Presentation type: Talk

Summary:

We do not understand fully the mechanisms driving the clumpy, very copious mass loss from Mira-like stars and red supergiants, nor how apparently solitary, non-rotating stars produce bipolar superwinds towards the end of the AGB. MERLIN and VLBI monitoring resolves evolved star winds on AU-scales, revealing how cloud sizes appear to depend on the stellar mass. Our MERLIN measurements differentiate between models for matter-bounded and amplification-bounded masers. The water clouds are usually, on average, spherical, but some become flattened around Miras with additional evidence of shocks. Comparison with Pushchino single-dish monitoring suggests that the clouds persist for many years but masers may blink on and off. The water maser clouds are denser than their surroundings, which support hydroxyl masers. Combining e-MERLIN and the EVN will allow a similar analysis of OH maser beaming in lower-density material, possibly revealing shocks at the interface between biconical outflows and older more spherical shells. ALMA will provide small-scale abundance measurements, resolving thermal molecular and dust emission as well as (sub-)mm masers. This will show whether the clouds seen in water masers are chemically distinct or are differentiated solely by temperature, density etc. Direct imaging of the stellar continuum with ALMA, e-MERLIN and EVLA, will test the suggestion of a direct relationship between the wind clumping scales and stellar convection cells.

The mysterious barium stars and their relatives

Author: Robert Izzard

Argelander Inst. for Astronomy, University of Bonn

Co-Authors: Tyl Dermine (Universite Libre de Bruxelles)

Session: UNS: Unsolved problems of post-main sequence stellar evolution

Presentation type: Talk

Summary:

The barium stars are G/K giants which contain copious amounts of barium but are not evolved enough to have made it themselves. Instead they acquired their heavy metal from a now dead AGB companion star. Canonical theory of mass transfer and tidal circularization suggests that barium stars with periods less than about twenty years should have circular orbits. That they do not is a serious problem for our understanding of AGB and/or binary-star physics. We investigate by simulating populations of Ba stars and find that our models only match the observed eccentricities and periods if we introduce some exotic new physics, for example a stellar kick at the end of the AGB or interaction with a circumbinary disc.

A pilot study for combined Doppler and interferometric imaging of post main-sequence stars

Author: Ettore Pedretti

School of Physics and Astronomy, University of St Andrews

Co-Authors: J. D. Monnier (University of Michigan), P. Petit (Laboratoire Astrophysique de Toulouse), J-F. Donati (Laboratoire Astrophysique de Toulouse), A. C. Cameron (University of St Andrews)

Session: UNS: Unsolved problems of post-main sequence stellar evolution

Presentation type: Talk

Summary:

The understanding of stellar magnetic fields is one of the â€œunsolved questionsâ€ in stellar astrophysics. While solar magnetism is well-studied and subject to detailed quantitative and rigorous analysis, magnetic cycles and activity for post main-sequence stars are still only qualitatively understood. Doppler and interferometric imaging are both well-established methods for imaging the surfaces of stars. Up until now, no systematic study was undertaken to combine these approaches on the same targets and rigorously test the limits of each technique. We present here a pilot study on the magnetically active RS CVn binary Zet And = HD 4502 that was imaged using long-baseline interferometry and the Doppler technique.

Testing mass-radius relations with eclipsing white dwarf / M dwarf binaries

Author: Steven Parsons

University of Warwick

Co-Authors: T.R.Marsh (University of Warwick); B.T.Gaensicke (University of Warwick)

Session: UNS: Unsolved problems of post-main sequence stellar evolution

Presentation type: Talk

Summary:

Most stars in the Galaxy are of low mass, and most stellar remnants are white dwarfs. A proper understanding of the structure of low mass stars and white dwarfs is of fundamental importance for a wide range of astrophysical problems, ranging from exo-planets to SNIa. Eclipsing binaries offer a way to directly measure stellar masses and radii. While this method is routinely used for intermediate stars, only a handful of eclipsing binaries containing low mass stars and white dwarfs are known. In this talk I will show how detailed studies of these systems can lead to masses and radii of unrivalled precision, good enough to test models of stellar structure and binary evolution.

Radial velocity measurements of Subdwarf B stars

Author: Chris Copperwheat

University of Warwick

Co-Authors: L. Morales Rueda, T.R. Marsh (Warwick), P.F.L. Maxted (Keele), U. Heber (Bamberg)

Session: UNS: Unsolved problems of post-main sequence stellar evolution

Presentation type: Talk

Summary:

Subdwarf B (sdB) stars are hot, subluminous stars which are thought to be core-helium burning with thin hydrogen envelopes. The mechanism by which these stars lose their envelopes has been controversial but it has been argued that binary star interaction is the main cause. Over the past decade we have been conducting a radial velocity study of a large sample of sdB stars, and with the discovery of more than fifty new binaries we have shown that a significant fraction of the field sdB population exists in binary systems. I will discuss some of the key results of our survey, including the binary fraction, the nature of the companion stars themselves and the period distribution. I will also discuss our continuing search for the long period systems which are predicted to make up the majority of the binary sdB population, but have to date remained elusive.

The Orientations of Galactic Bulge Planetary Nebulae

Author: Bryan Rees

The University of Manchester

Co-Authors: A.A.Zijlstra (The University of Manchester)

Session: UNS: Unsolved problems of post-main sequence stellar evolution

Presentation type: Talk

Summary:

Planetary nebulae are formed from the ejected envelopes of evolved stars. We have investigated the alignment of a sample of 130 such nebulae in the Galactic bulge. We found that the alignment of the sub-sample of 44 nebulae with bipolar morphology (34% of the total sample) is not random. The Kuiper test for uniformity returns a p-value of 0.001, (equivalent to a better than 3Ïƒ significance level were the distribution Gaussian). The alignments of the bipolar nebulae peak approximately along the Galactic plane. Consequently, if the binary star hypothesis for the formation of bipolar nebulae is correct, binary systems in the Galactic bulge have angular momentum vectors that are preferentially aligned along the Galactic plane.

White dwarfs and the local interstellar environment

Author: Martin Barstow

University of Leicester

Co-Authors: S.L. Casewell (University of Leicester), N.J. Dickinson (University of Leicester)

Session: UNS: Unsolved problems of post-main sequence stellar evolution

Presentation type: Talk

Summary:

The relationship between white dwarfs and the local interstellar medium (LISM) is intimate and complex. The production of white dwarfs recycles significant quantities of material, mainly CNO, into the LISM. UV spectroscopic observations of white dwarfs are able to resolve the various environments in velocity space, including: the stellar photosphere, circumstellar region and LISM clouds. A complex picture is revealed raising several questions: 1) What is the origin of the heavy elements in white dwarf atmospheres? 2) What is the nature of the circumstellar material observed in a number of stars? 3) How does this material interact with the LISM? A large database of UV observations of white dwarfs exists from the FUSE mission and we are now obtaining important new observations with the COS spectrograph installed on HST. We present the first results from detailed analyses of these data.

A Highly Eccentric, Short Period Binary with Î´ Scuti Pulsations

Author: Kelly Hambleton

UCLan

Co-Authors: D. Kurtz (Jeremiah Horrocks Institute, UCLan); S. Bloemen (Institute for Astronomy, K. U. Leuven); J. Southworth (Astrophysics group, Keele University)

Session: UNS: Unsolved problems of post-main sequence stellar evolution

Presentation type: Poster

Summary:

The Kepler star presented is an eclipsing binary with two stellar components. The primary component is an early A type main sequence star with an approximate temperature of ~8255K, whilst the secondary component is a late F/early A type main sequence star with its temperature comparable to that of the primary. It is currently unknown which component, if not both, is a Î´ Scuti star. The orbital period of this system is observed to be 2.189 days, with the light curve demonstrating clear ellipsoidal variability and a hump after secondary minimum. This type of variation indicates tidal distortion and extreme interstellar heating. The binary system has been modelled using a the Wilson and Devinney (1971) code (WD), in conjunction with a wrapper made by Southworth et al. (2011), which generates automatic iterations. The frequency spectrum of the pulsation data (the original data with the binary characteristics subtracted) contains both p and g modes. Eight of the g modes are precise multiples of the orbital frequency, to an accuracy greater than 3 Ïƒ. This is indicative of the resonant excitation of free Eigen frequencies.

R Cassiopeiae: Circumstellar Envelope SiO Maser

Author: Khudhair A. Assaf

JBCA, University of Manchester

Co-Authors: Diamond P. J., Richards A. M. S. and Gray M.

Session: UNS: Unsolved problems of post-main sequence stellar evolution

Presentation type: Poster

Summary:

We present 23 epochs total intensity images of 43GHz, v=1, j=1-0 SiO maser emission toward Mira variable R Cas. Data were recorded at each VLBA antenna at approximate monthly sampling over an optical pulsation phase range of Ï†= 0.158 to Ï† = 1.783. These maps show ring-like structure of distribution of the maser features in the shell around the star at a distance almost 1.62 times of the radius of star(R*) from the star's centre. We compare the results with a model produced by Gray et. al. 2009.

A Semi-Automated Approach to the Abundance Analysis of Ap Stars

Author: Martin Hall

University of Central Lancashire

Co-Authors: H.Bruntt (University of Aarhus); V.Elkin (University of Central Lancashire); D.W.Kurtz (University of Central Lancashire)

Session: UNS: Unsolved problems of post-main sequence stellar evolution

Presentation type: Poster

Summary:

A preliminary analysis of elemental abundances has been performed on a series of high-resolution spectra belonging to approximately 350 Ap stars collected by the FEROS Echelle spectrograph (Fibre-fed, Extended Range, Ã‰chelle Spectrograph) located on the 2.2m telescope at La Silla Chile over the period 2007-2010. The technique, calibrated by comparison with standard manual techniques, used a semi-automated set of routines to calculate equivalent widths for a selected number of spectral lines, which were then used to generate abundances using the WIDTH9 program (references). The VWA (v sin i, wavelength shift, abundance analysis) software package was used to determine spectral line sets for analysis, generate spectral plots, and investigate issues of blending and velocity-broadening. Some early results of the survey are presented here.

How Stellar Evolution Uncertainties Affect Planetary Endstates

Author: Dimitri Veras

Institute of Astronomy, Cambridge University

Co-Authors:

Session: UNS: Unsolved problems of post-main sequence stellar evolution

Presentation type: Poster

Summary:

A variety of stellar systems, including those with extreme horizontal branch stars and pulsars, are known to host planets. Changes in the particular evolutionary path of a post-main sequence star can have drastic effects on planetary orbital parameters and ultimately a planet's chance for survival. Here, we analyze the effect of sudden and/or nonlinear stellar mass and radius changes on planetary systems, particularly when a star undergoes a phase transition or exhibits an outburst. We relate these findings to uncertainties in post-main sequence stellar evolution, and quantify the range of planetary endstates allowed by these uncertainties.

Tidings from the Hot Eruptive Corona

Author: Claire Foullon

CFSA, Physics Department, University of Warwick

Co-Authors:

Session: WAV: Waves and transients

Presentation type: Talk

Summary:

The ever-increasing number and quality of observations of the hot corona (e.g. from RHESSI and SDO) are ideally suited to investigate the role of waves and instabilities in energetic events, such as flares and coronal mass ejections (CMEs). The solar events are the source of flows and global transients that often excite resonant kink modes of MHD waves in neighbouring coronal structures. Of particular interest is the detection of quasi-periodic pulsations (QPPs) in solar flares and their relevance for the formation of 'plasmoids' above flare loops and the periodic release of energetic particles in the solar wind. A recent multi-wavelength analysis of spatially-resolved QPPs reveals that they may result from a fine balance between scale sizes and dominant energetic processes. An external resonator gives rise to the long-period QPPs only when certain conditions are fulfilled. Moreover, SDO is now giving us the first observations of the temporally and spatially resolved evolution of the magnetic Kelvin-Helmholtz (KH) instability, which is seen developing at the surface of a fast coronal mass ejecta. The non-linear effects, multi-scale and microphysical interactions inherent to the flow-driven instabilities can play a major role not only in the transient kinematics by enhancing the drag in localised regions, but also in the plasma entry across discontinuities. The new findings highlight the relevance of waves and instabilities into the dynamics of rarefied magnetised plasmas and key eruptive phenomena of our Sun-Earth system.

Direct evidence for sausage modes in photospheric magnetic flux tubes

Author: Richard Morton

University of Sheffield

Co-Authors: R. Erdelyi

Session: WAV: Waves and transients

Presentation type: Talk

Summary:

It is well established that the layers of the solar atmosphere are connected by a vast, complex network of magnetic field lines. These field lines form distinct magnetic structures which can act as waveguides, channeling energy from the solar surface to the upper layers of the atmosphere. To be able to asses the nature of the energy transport we need to be able to track waves generated below/at the surface as they progress through the atmosphere. This should be possible through the lower layers (photosphere/chromosphere) of the solar atmosphere using the Rapid Oscillations of the Solar Atmosphere (ROSA) imaging system. This should also open up novel avenues for magneto-seismology of the lower solar atmosphere. We present here the first in a series of observations using the ROSA system situated at the Dunn Solar Telescope (NSO, Sac Peak). The observations are from the ROSA commissioning run and we obtain the first direct observations of relatively high frequency sausage modes in the photosphere. We report the observations of sausage MHD oscillations in a series of magnetic pores in the 6170~A (blue continuum) line and report out of phase oscillations in pore area and intensity with periods in the range 30s-450s.

Helioseismic analysis of first SDO sun-quake

Author: Sergei Zharkov

MSSL, UCL

Co-Authors: S.A.Matthews, E.Pedram, L.Green, V.V.Zharkova

Session: WAV: Waves and transients

Presentation type: Talk

Summary:

We present results of helioseismic investigation of the acoustically active X-class flare of February 15, 2011, observed by Solar Dynamics Observatory. We apply acoustic holography to HMI data to locate acoustic sources associated with this flare in the photosphere. We carry out frequency and time-distance analysis to determine properties of such sources. The locations and strengths of seismic signatures are compared with other AIA and RHESSI measurements. Possible implications of these findings for physical processes in this flare are discussed.

The response of a 3D solar atmosphere to wave-driven jets

Author: Eamon Scullion

Institute of Theoretical Astrophysics, University of Oslo

Co-Authors: R. Erdelyi (University of Sheffield), V. Fedun (University of Sheffield), J. G. Doyle (Armagh Observatory)

Session: WAV: Waves and transients

Presentation type: Talk

Summary:

Global oscillations from the solar interior are, mainly, pressure-driven (p-mode) oscillations which appear with a peak power of 5 minute period. These oscillations are considered to manifest in many phenomena in the lower solar atmosphere, most notably, spicules (otherwise known as fibrils and mottles). These small-scale jets are highly abundant in the lower-to-mid solar atmosphere and may provide the key to understanding the powering mechanisms of the transition region (TR) and lower corona. Wave-driven (type~I) spicules, with 5~min periodicity, may be important in the energizing processes which heat the mid-to-upper atmosphere. Here we simulate the formation of type-I spicule phenomena in 3-D and the transmission of acoustic waves from the lower chromosphere, through the TR, and into the corona. The outer atmosphere oscillates in response to the jet formation, and in turn, we reveal the formation of a circular seismic surface wave which we name as a TRQ (Transition Region Quake). The TRQ forms as a consequence of an upward propelling spicular wave-train that repeatedly punctures and energizes the TR. The TRQ becomes guided along the TR and slowly loses momentum and energy. We suggest the TRQ formation, arising from spicules, as a formidable mechanism in continuously sustaining part of the energy budget of the TR. In support of our numerical model, and validating purposes of our theory, we present a multi-instrument analysis of an on-disk jet, with associated TRQ.

Investigating the properties of the solar corona using large-scale transients

Author: Peter Gallagher

Trinity College Dublin

Co-Authors:

Session: WAV: Waves and transients

Presentation type: Talk

Summary:

The solar corona is a hot, tenuous plasma threaded by magnetic fields and which varies on time-scales ranging from microseconds to millennia. The thermodynamic properties of the corona, such as density and temperature, are now well understood, but there remains many questions regarding the corona magnetic field, and in particular, its topology and variability. Over the past decade, developments in coronal seismology and theoretical simulations have provided a new understanding of the fundamental building block of the corona, coronal loops. More recently, full-disk observations using the increased cadences of STEREO/EUVI, Hinode/XRT and SDO have enabled us to study the propagation of large-scale transient features (e.g., â€œEIT wavesâ€ and CMEs) and their interaction with coronal structures. In this talk, I will review these large-scale transient phenomena, and how they are now giving new insights into the fundamental properties of the enigmatic solar atmosphere.

Propagating Coupled AlfvÃ©n and Kink Oscillations in an Arbitrary Inhomogeneous Corona

Author: David Pascoe

University of St Andrews

Co-Authors: A.N.Wright; I.De Moortel

Session: WAV: Waves and transients

Presentation type: Talk

Summary:

Observations have revealed ubiquitous transverse velocity perturbation waves propagating in the solar corona. We perform 3D numerical simulations of broadband footpoint-driven transverse waves propagating in a low Î² plasma. When density structuring is present, mode coupling in inhomogeneous regions leads to the coupling of the kink mode to the AlfvÃ©n mode. The frequency-dependent decay of the propagating kink wave is observed as energy is transferred to the local AlfvÃ©n mode. For all density structures considered, modest changes in density were capable of efficiently converting energy from the driving footpoint motion to localised AlfvÃ©n modes. This has the consequence that transverse footpoint motions at the base of the corona will deposit energy to AlfvÃ©n modes in the corona.

Magnetacoustic shock formation near a magnetic null point

Author: Marcin Gruszecki

University of Warwick

Co-Authors: M. Gruszecki, S. Vasheghani Farahani, V. M. Nakariakiov, T. D. Arber

Session: WAV: Waves and transients

Presentation type: Talk

Summary:

Interaction of nonlinear fast magnetoacoustic waves with a magnetic null point is investigated in the context of triggering solar flares. Propagation of fast, initially axisymmetric waves towards a two dimensional isothermal magnetic null point is modelled in terms of ideal magnetohydrodynamic equations. Dynamics of initially axisymmetric fast pulses of small amplitude is found to be consistent with the linear analytical solution of Craig and McClymont (1991). The increase in the amplitude leads to the nonlinear acceleration of the compression pulse and deceleration of the rarefaction pulse, and hence the distortion of the wave front. The pulse experiences nonlinear steepening in the radial direction, either on the leading or the back slopes, for the compression and rarefaction pulses, respectively. The nonlinear steepening leads to the generation of sharp spikes of the electric current density. As in the uniform medium, the position of the shock formation depends also upon the initial width of the pulse. Only sufficiently smooth and low-amplitude initial pulses can reach the vicinity of the null point, create there current density spikes, and hence initiate magnetic reconnection by seeding anomalous electrical resistivity. Steeper and higher amplitude initial pulses overturn at larger distance from the null point, and cannot trigger reconnection.

Observations using LYRA of two simultaneous oscillation modes in a single QPP event

K.U.Leuven

Co-Authors: A. De Groof (ESA); J. Zender (ESA); D. Berghmans (Royal Observatory Belgium)

Session: WAV: Waves and transients

Presentation type: Talk

Summary:

We analyse lightcurves from the LYRA irradiance experiment onboard PROBA2, during the flare of 8th of February 2010. We see both long and short period oscillations during the flare. The long period oscillation is interpreted in terms of standing slow modes, the short period oscillation is thought to be the standing sausage mode. This is the first time two oscillation modes are measured simultaneously in coronal structures. The periods are used to measure the plasma-$\beta$.

The effect of variable background on oscillating hot coronal loop due to thermal conduction

Author: KHALIL AL-GHAFRI

University of Sheffield

Co-Authors: R. Erdelyi

Session: WAV: Waves and transients

Presentation type: Talk

Summary:

We investigate the effect of a variable, i.e. time-dependent, background on the standing acoustic mode generated in hot coronal loop. A theoretical model of 1D semicircular shape describing the geometry of the coronal loop is used. The background temperature is allowed to change as a function of time and undergoes an exponential decay with characteristic cooling times typical for coronal loops. The magnetic field is assumed to be uniform and straight. Thermal conduction is the dominant mechanism of cooling the background plasma in the presence of an unspecified thermodynamic source. The influence of the cooling background plasma on the behaviour of standing acoustic waves is investigated analytically. The time-dependent dispersion relation and wave amplitude are derived by using the WKB theory and the analytical solution is obtained with the aid of method of characteristics. Numerical evaluations are used to illustrate the behaviour of the standing acoustic waves in a system with variable, time-dependent background. The results are applied to a number of detected loop oscillations. We find a remarkable agreement between the theoretical predictions and the observations.

AlfvÃ©n wave phase mixing and damping in the ion cyclotron range of frequencies

Author: James Threlfall

University of St Andrews

Co-Authors: K. G. McClements (EURATOM/CCFE Fusion Association); I. De Moortel (University of St Andrews)

Session: WAV: Waves and transients

Presentation type: Talk

Summary:

We determine the effect of the Hall term in Ohmâ€™s law on AlfvÃ©n wave dissipation in the ion cyclotron frequency range. Damping in a uniform plasma is treated analytically, whilst a Lagrangian fluid code (Lare2d) is used to study the damping and phase mixing of an initially Gaussian field perturbation, in both a uniform magnetic field (with an equilibrium density gradient) and an x-point field (with uniform density). The magnetic energy associated with an initially Gaussian field perturbation in a uniform resistive plasma is shown to decay algebraically at a rate that is unaffected by the Hall term to leading order in k^2di^2 where k is wavenumber and di is ion skin depth. A similar decay law applies to whistler perturbations in the limit k^2di^2 >> 1. We demonstrate that in both geometries considered, the inclusion of the Hall term reduces the effectiveness of phase-mixing in plasma heating. The reduction in the damping rate in the uniform field (non-uniform density) case, which arises from dispersive effects, tends to zero in both the weak and strong phase mixing limits. The reduction in the damping rate in the Hall MHD x-point case indicates that this effect is generic to Hall MHD plasma configurations which contain a variation in AlfvÃ©n speed. This work was partly funded by the RCUK Energy Programme under grant EP/I501045 and the European Communities under the contract of Association between EURATOM and CCFE. The views and opinions expressed herein do not necessarily reflect those of the European Commission.

Kinetic Alfven waves and the heating of the solar wind

Author: XING LI

Aberystwyth University

Co-Authors:

Session: WAV: Waves and transients

Presentation type: Talk

Summary:

Despite that the solar wind was discovered over fifty years ago, â€œhow the solar wind is heated and acceleratedâ€ remains an unanswered question. In this paper, I will review the observational and theoretical progresses regarding the issue. Plasma turbulence at kinetic scales is widely believed to play a key role in the solar wind heating and acceleration process. However, our attempt to understand the solar wind heating is hindered by our lack of a complete knowledge of the plasma turbulence. A lot of early investigations have focused on the role of parallel propagating ion cyclotron waves driven by plasma turbulence. However, recent observations of electromagnetic spectrum of the solar wind plasma turbulence at kinetic scales indicate that kinetic Alfven waves may be very important. I will discuss some new ideas regarding the nonlinear dissipation of Alfven waves whose frequency is not significantly lower than the ion gyrofrequency and their subsequent heating effect to ions for both low (the inner corona) and high (interplanetary space) beta plasmas. Numerical calculations suggest that these waves are able to produce higher perpendicular than parallel (to the background magnetic field) ion temperatures in low beta plasmas. However, in high beta plasmas, these waves are not effective in heating ions in the direction perpendicular to the background magnetic field. We will discuss the relevance of the study to the solar wind observations.

Leakage of long-period oscillations from the chromosphere to the corona

Author: Ding Yuan

CFSA, Department of Physics, University of Warwick

Co-Authors: V. M. Nakariakov (1,2) N. Chorley (1) C. Foullon (1) 1. Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL, UK 2. Central Astronomical Observatory at Pulkovo of the Russian Academy of Sciences, 196140 St Petersburg, Russia

Session: WAV: Waves and transients

Presentation type: Poster

Summary:

Long-period oscillations in a coronal diffuse structure are detected with the Transition Region And Coronal Explorer (TRACE). The EUV images of the NOAA active region 8253 are available in 171 Ã… and 195 Ã… bandpasses from 30 June to 4 July 1998. As expected, the average intensity variation is connected with the CCD temperature, which varies with the orbital motion of the spacecraft. Hence, oscillations with the orbital period and its higher harmonics appear as artifacts in the light curves. After the exclusion of the orbital effects, we identified several long-period oscillations in the diffuse fan-like structure of the active region. Similar periodicities were detected in the microwave emission from the chromospheric part of that active region, observed with the ground-based Nobeyama Radioheliograph (NoRH) in the 17 GHz channel. It was found that 28 and 72 min oscillations were present in both EUV and microwave emission. From the period values, the detected oscillations could be associated with gravity-driven solar interior modes. The appearance of these oscillations in the coronal part of the active region may be connected with the wave leakage or the evanescence of chromospheric oscillations.

Resonantly damped propagating kink waves in longitudinally stratified solar waveguides

Author: Roberto Soler

Centre for Plasma Astrophysics. KU Leuven (Belgium)

Co-Authors: J. Terradas (B); G. Verth (A,C); M. Goossens (A). Inst. A: Centre for Plasma Astrophysics. KU Leuven (Belgium) Inst. B: Solar Physics Group. University of the Balearic Islands (Spain) Inst. C: School of Computing, Engineering and Information Sciences, Northumbria University (UK)

Session: WAV: Waves and transients

Presentation type: Poster

Summary:

It has been shown that resonant absorption is a robust physical mechanism to explain the observed damping of magnetohydrodynamic (MHD) kink waves in the solar atmosphere due to naturally occurring plasma inhomogeneity in the direction transverse to the direction of the magnetic field. Theoretical studies of this damping mechanism were greatly inspired by the first observations of post-flare standing kink modes in coronal loops using the Transition Region And Coronal Explorer (TRACE). More recently, these studies have been extended to explain the attenuation of propagating coronal kink waves observed by the Coronal Multi-Channel Polarimeter (CoMP). In the present study, for the first time we investigate the properties of propagating kink waves in solar waveguides including the effects of both longitudinal and transverse plasma inhomogeneity. Importantly, it is found that the wavelength is only dependent on the longitudinal stratification and the amplitude is simply a product of the two effects. In light of these results the advancement of solar atmospheric magnetoseismology by exploiting high spatial/temporal resolution observations of propagating kink waves in magnetic waveguides to determine the length scales of the plasma inhomogeneity along and transverse to the direction of the magnetic field is discussed.

Transverse Coronal Loop Oscillations Seen in Unprecedented Detail by SDO/AIA

Author: Rebecca White

University of Warwick

Co-Authors: E.Verwichte (University of Warwick)

Session: WAV: Waves and transients

Presentation type: Poster

Summary:

We Present an observational study of transverse oscillations of several coronal loops observed in three separate events using data from the Solar Dynamics Observatory (SDO) which provides unprecedented temporal and spatial resolution of the solar corona. We study oscillatory events using the Atmospheric Imaging Assembly (AIA) instrument on board SDO, primarily in the 171Ã… bandpass to obtain information on loop lengths, periods and damping times. Where possible, data from SDO/AIA has been complimented with data from STEREO in order to obtain an estimation of loop inclination angles. Transverse oscillations in solar coronal structures have important applications for coronal seismology where the diagnostic power of the transverse waves can provide information on coronal magnetic and density structuring. Also oscillating loops are often observed to be at or near the site of flares and so can provide information about the physical conditions in the vicinity of these events.

Slow Magnetoacoustic Waves in Two-Ribbon Flares

Author: Valery Nakariakov

University of Warwick

Co-Authors: I.V. Zimovets (Space Research Institure of RAS, Moscow, Russia)

Session: WAV: Waves and transients

Presentation type: Poster

Summary:

We demonstrate that disturbances observed to propagate along the axis of the arcade in two-ribbon solar flares at the speed of a few tens km/s, well below the AlfvÂ´en and sound speeds, can be interpreted in terms of slow magnetoacoustic waves. The waves can propagate across the magnetic field, parallel to the magnetic neutral line, because of the wave-guiding effect due to the reflection from the footpoints. The perpendicular group speed of the perturbation is found to be a fraction of the sound speed, which is consistent with observations. The highest value of the group speed grows with the increase in the ratio of the sound and AlfvÂ´en speeds. For a broad range of parameters, the highest value of the group speed corresponds to the propagation angle of 25-28 degrees to the magnetic field. This effect can explain the temporal and spatial structure of quasi-periodic pulsations observed in two-ribbon flares.

Spatial seismology of a large coronal loop from EUV observations of its transverse oscillations

Author: Erwin Verwichte

University of Warwick

Co-Authors: C.Foullon (University of Warwick); T.Van Doorsselaere (Katholieke Universiteit Leuven, Belgium)

Session: WAV: Waves and transients

Presentation type: Poster

Summary:

We present a study of transverse loop oscillations in a large coronal loop arcade, using observations from TRACE and EIT/SoHO. For the first time we reveal the presence of long-period transverse oscillations with periods between 24 minutes and 3 hr. One loop bundle, 690 Mm long and with an oscillation period of 40 minutes, is analysed in detail. The oscillation quality factor is similar to what has been found earlier for oscillations in much shorter loops. This indicates that the damping mechanism of transverse loop oscillations is independent of loop length or period. The displacement profile along the whole length of the oscillating loop is determined for the first time. By comparing the observed profile with models of the three-dimensional geometry of the equilibrium and perturbed loop, we test the effect of longitudinal structuring (spatial seismology) and find that the observations cannot unambiguously distinguish between loop structuring and non-planarity. Associated intensity variations with a similar periodicity are discussed. Also, we report intensity oscillations at the loop footpoint, which are in anti-phase with respect to the intensity oscillations in the loop body. Lastly, this observation offers the first opportunity to Alfven speed profile in the global corona.

Damped large amplitude transverse oscillations in an EUV solar prominence

Author: Jennifer (Harris) Hershaw

University of Warwick

Co-Authors: C.Foullon (University of Warwick); V.M.Nakariakov (University of Warwick, Pulkovo Observatory); E.Verwichte (University of Warwick)

Session: WAV: Waves and transients

Presentation type: Poster

Summary:

We investigate two successive trains of large amplitude transverse oscillations in an arched EUV prominence, observed with SOHO/EIT on the North-East solar limb on 30 July 2005. The oscillatory trains are triggered by large-scale coronal waves, associated with two flares occurring in a remote active region. The oscillations are tracked within rectangular slits parallel to the solar limb at different heights, which move with the apparent height profile of the prominence to account for solar rotation. Time series for the two prominence arch legs are extracted using Gaussian fitting on the 195 Ã… absorption features, and fitted to damped cosine curves to determine the oscillatory parameters. We find agreement between the differing energies of the triggering flares and associated waves, and the velocity amplitudes of the two oscillatory trains. The oscillation period is similar for both trains, indicating a characteristic frequency as predicted by magnetohydrodynamics. The prominence exhibits a global kink mode to a first approximation; however there are also indications that it oscillates as a collection of interacting threads. Combining our results with those of previously analysed kink oscillations in loops, we find an approximately linear dependence of damping time upon period, supporting resonant absorption as the damping mechanism.

Small-scale HÎ± jets in the solar chromosphere

Author: David Kuridze

Astrophysics Research Centre, Queen

Co-Authors: M. Mathioudakis ( Astrophysics Research Centre, School of Mathematics and Physics, Queenâ€™s University Belfast ), D. B. Jess ( Astrophysics Research Centre, School of Mathematics and Physics, Queenâ€™s University, Belfast ), S. Shelyag ( Astrophysics Research Centre, School of Mathematics and Physics, Queenâ€™s University Belfast),

Session: WAV: Waves and transients

Presentation type: Poster

Summary:

We study the horizontal velocities associated with small-scale HÎ± jets in a decaying active region. Our dataset comprises of simultaneous imaging in HÎ±, Ca K, G-band, and line-of-sight magnetograms. The observations were obtained with the ROSA imaging system at the Dunn Solar Telescope. The HÎ± images are highly dynamic, displaying jet velocities as high as 35 km/s. At the photopsheric level, the origin of the jets is associated with Ca K brightenings and G-band bright points. We suggest that the siphon flow model of Doyle et al. (2006) is suitable for interpretation of our observation. The observed HÎ± jets can be considered as siphon flows in the chromospheric loop, driven by the heating pulse at one of the loop footpoints.

Period persistence of long period oscillations in sunspots

Author: Nicky Chorley

CFSA, Physics Department, University of Warwick

Co-Authors: C. Foullon (University of Warwick), B. Hnat (University of Warwick), V. M. Nakariakov (University of Warwick), and K. Shibasaki (Nobeyama Solar Radio Observatory/NAOJ, Japan)

Session: WAV: Waves and transients

Presentation type: Poster

Summary:

Long period oscillations in the microwave radiation intensity generated over the sunspot of NOAA AR 10330 are studied with the Nobeyama Radioheliograph as the sunspot passes over the solar disk, over the course of 9 days (06-15 April 2003). Periodogram, Fourier and global wavelet analyses reveal the presence of a significant oscillatory component in the range P ~ 50-120 min over the course of the observations. The spectral amplitudes of five significant Fourier components in the range P = 50-150 min are also seen to be stable over the observations, when the data are not affected by changes in magnetic configuration in the region. The ground-based nature of the instrument naturally introduces long data gaps in such long duration observations and the presence of the gaps does not allow any conclusion as to the stability of the phases of the oscillations. As a model to explain the persistence of the dominant long periods, a simple oscillator with a nonlinear driving term is proposed. The spectral difference between distinct peaks within, e.g. the 3 min spectral band, are shown to be able to resonate with the long period one hour oscillations.

Velocity flows inside NOA AR 10720 derived by temporally evolving ring diagram analysis

Aberystwyth University

Co-Authors: K. Burrows (Aberystwyth University)

Session: WAV: Waves and transients

Presentation type: Poster

Summary:

Between 13th and 16th January 2005, NOA active region 10720 was the site of several large flare events. On 15th January, an X1.2 class flare became seismically active and produced one of the largest flare-induced quakes ever observed by the SOHO spacecraft. The quake rapidly expanded into the surrounding active-region plasma causing a disturbance to the internal velocity fields within the region. Using a temporal scanning technique for helioseismic ring diagram analysis of SOHO/MDI dopplergrams, we have calculated the internal flows of the region and the subsurface factors which might have contributed to the quake event.

First | Previous | Next | Last | All