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RAS PN06/09 (NAM3): Colliding Neutron Stars Produce the Strongest Magnetic Fields in the Universe

Last Updated on Sunday, 01 December 2013 20:40
Published on Thursday, 30 March 2006 00:00
price_rosswog_press_1.jpgThe first computer simulation to model the collision of two magnetised neutron stars shows that the impact generates the strongest magnetic fields known in the Universe.  The gigantic fields are more than a thousand million million times stronger than the magnetic field of the Earth and are thought to launch the violent gamma-ray burst explosions.


Neutron stars have masses comparable to that of our Sun, but a radius of only 10 km, so they are even denser than atomic nuclei.  Neutron stars that orbit around each other in binary systems will, according to Einstein’s Theory of General Relativity, slowly spiral in towards each other. Their final fate is a thunderously violent collision.

The results of simulations of these collisions are being presented at the Royal Astronomical Society’s National Astronomy Meeting on 5th April and at the Ringberg-conference on Nuclear Astrophysics on the 7th April. They are published in the online journal Science Express on 30th March.

Dr. Daniel Price from the University of Exeter, UK, said, "It is only recently that we have the computing power available to model the collisions and take into account the effects of magnetic fields. It has taken us months of nearly day and night programming to get this project running."  Prof. Stephan Rosswog from the International University of Bremen, Germany, adds "This is an incredible result. Magnetic fields that we are familiar with, say from a magnet at your refrigerator, have strength of about 100 Gauss. Such a collision produces field that are an incredible 10 million million times stronger."

In the supercomputer simulations, Price and Rosswog show that within the first millisecond of the collision, magnetic fields are produced that are stronger than any other magnetic field that is known in the Universe.  The calculations are a computational challenge because they include a lot of exotic physics, including effects of high-density nuclear physics, particle physics and General Theory of Relativity. To calculate only a few milliseconds of a single collision takes several weeks on a parallel supercomputer.

It has long been suspected that such a collision may be at the heart of some of the brightest explosions in the Universe since the Big Bang, so-called short gamma-ray bursts. Recent detections of 'afterglows' of such bursts have confirmed this idea, but much of the physics behind these explosions lies still in the dark.

NOTES FOR EDITORS:

The 2006 RAS National Astronomy Meeting is hosted by the University of Leicester and sponsored by the Royal Astronomical and the UK Particle Physics and Astronomy Research Council (PPARC).
For further information see: http://www.nam2006.le.ac.uk/

The 13th Workshop on Nuclear Astrophysics, held at the Ringberg Castle, will bring together astrophysicists, nuclear physicists, and astro-particle physicists in order to discuss topics of common astrophysical interest.  The workshop is organised by the Max Planck Institut fur Astrophysik.

For further information see: http://www.mpa-garching.mpg.de/Hydro/NucAstro/workshop.html

Science Express: http://www.sciencemag.org/sciencexpress/recent.dtl

IMAGES:

For animations and stills from the supercomputer simulation, see:


Image captions:
1125102cover.jpg: A snapshot from the coalescence of two magnetized neutron stars, showing magnetic field strengths in the material at and below the orbital plane. Blue corresponds to the unamplified magnetic field whilst yellow/white indicates material with magnetic field strengths higher than even those found in magnetars. The two stars have merged together in just a few milliseconds, shedding mass into spiral arms that are subsequently wrapped around the central object to form a hot torus. The magnetic field is amplified in the shear instability between the stars which is clearly visible in the central regions.  The snapshot shows the configuration ~4 milliseconds after the merger and dimensions are ~140km from left to right.

1125201panels_clean.jpg and 1125201panels_nocolourbar.jpg: Snapshots (left to right, top to bottom) of the coalescence of two magnetised neutron stars, showing magnetic field strengths in the material at and below the orbital plane. Dimensions in each panel are ~140 km from left to right. The stars move gradually towards each other and then merge in a ``plunging phase'' within about one orbital period (~2 ms; first two snapshots). This object sheds mass into spiral arms that are subsequently wrapped around the central object (snapshots three to five) to form a hot torus (last snapshot).  The magnetic field is amplified in the shear instability between the stars and subsequently advected with the matter to cover the surface of the central merger remnant.

1125201fullstars.jpg: A snapshot from the coalescence of two magnetized neutron stars, showing magnetic field strengths in the material at the surface of the merged object: Blue corresponds to the unamplified magnetic field whilst yellow/white indicates material with magnetic field strengths higher than even those found in magnetars. The two stars have merged together in just a few milliseconds, shedding mass into spiral arms that are subsequently wrapped around the central object to form a hot torus. The snapshot shows the configuration ~4 milliseconds after the merger and dimensions are ~140km from left to right.

Image Credits: Daniel Price and Stephan Rosswog.


CONTACT:

Dr. Daniel Price
School of Physics, University of Exeter,
Stocker Rd, Exeter EX4 4QL, UK
Phone:  +44 1392 264138
Fax:    +44 1392 264111
Email:  This email address is being protected from spambots. You need JavaScript enabled to view it.
Web : http://www.astro.ex.ac.uk/people/dprice/

Dr. Stephan Rosswog
Professor of Astrophysics, International University Bremen 
School of Engineering and Science, International University Bremen  
Campusring 1, 28759 Bremen, Germany
Phone: +49 421 200 3226
Fax:   +49 421 200 3229
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
Web: http://www.faculty.iu-bremen.de/srosswog