An international team of astronomers have undertaken a survey with a new submillimetre camera have discovered more than a hundred dusty galaxies in the early Universe, each of which is in the throes of an intense burst of star formation. One of these galaxies is an example of a rare class of starburst, seen just 1 billion years after the Big Bang.
ROYAL ASTRONOMICAL SOCIETY PRESS INFORMATION NOTE
16th April 2009
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Ref.: RAS PN 09/29 (NAM 16)
Dr Robert Massey
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RAS PN 09/29 (NAM 16, EMBARGOED): A (LESS)ER CHALLENGE TO GALAXY FORMATION
An international team of astronomers have undertaken a survey with a new submillimetre camera have discovered more than a hundred dusty galaxies in the early Universe, each of which is in the throes of an intense burst of star formation. One of these galaxies is an example of a rare class of starburst, seen just 1 billion years after the Big Bang. In her presentation on Wednesday 22nd April at the European Week of Astronomy and Space Science conference, team leader Dr. Kristen Coppin of Durham University will discuss the new results and how they may present a direct challenge to our current ideas of how galaxies formed.
The team (known as the LESS collaboration) used the new Large Apex Bolometer Camera (LABOCA) camera on the Atacama Pathfinder Experiment (APEX) telescope sited in the Atacama Desert in Chile to make a map of the distant galaxies in a region of the sky called the Extended Chandra Deep Field South. These galaxies are so far away that we see them as they appeared billions of years ago. LABOCA is sensitive to light at wavelengths just below 1mm (submillimetre radiation), and is able to find very dusty and very luminous galaxies at very early times in the history of the Universe. These submillimetre galaxies represent massive bursts of star formation associated with the early formation of some of the most massive galaxies in the present-day Universe: giant elliptical galaxies.
For many years it has been thought that these giant elliptical galaxies formed most of their stars at very early times in the Universe, within the first billion years after the Big Bang. However, very few examples of these very distant and very bright dusty sources have been found in submillimetre surveys, until the LESS collaboration completed their survey of a Full Moon-sized patch of sky in the southern hemisphere constellation of Fornax. Their survey is the largest and deepest of its kind in submillimetre radiation and reveals over a hundred galaxies that are forming stars at a prodigious rate.
Working with their new map, the team identified one of the submillimetre sources as being associated with a star forming galaxy which is seen just 1 billion years after the Big Bang. This remarkable galaxy shows the signatures of both intense star formation and obscured black hole growth when the Universe was only 10 percent of its current age. Dr. Coppin and the LESS team suggest that there could be far more submillimetre galaxies lurking at these early times than had previously been thought. Dr Coppin comments, “The discovery of a larger number of such active galaxies at such an early time would be at odds with current galaxy formation models”.
Dr. Kristen Coppin
Institute for Computational Cosmology
Tel: +44 (0)191 3343786
Prof. Ian Smail
Institute for Computational Cosmology
Tel: +44 191 3343605
Media & PR Officer
University of Hertfordshire
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The image shows the most distant submillimetre galaxy discovered by the LESS collaboration.
The main image shows a wide 3-colour optical image from the NASA/ESA Hubble Space Telescope (HST), overlaid by the contour map from the LESS survey made using the LABOCA submillimetre camera. Higher resolution radio and NASA Spitzer Space Telescope mid-infrared data have pinpointed the source of the submillimetre emission to the optical galaxy indicated by a box.
The observed energy output of the galaxy measured as a function of wavelength is plotted in the inset, showing that most of the energy is being emitted in the far-infrared and submillimetre from dust-reprocessed starlight.
Using spectroscopic data from the Keck telescope on Hawaii and the ESO VLT in Chile, the light travel time to the object is 12 billion years, meaning we are seeing it as it was just over 1 billion years after the Big Bang.
NOTES FOR EDITORS
THE LESS COLLABORATION
The Laboca ECDFS Submillimetre Survey (LESS) project is a joint survey of the Max Planck Gesellschaft and the European Southern Observatory. The project is led by Profs. Ian Smail (Durham University), Fabian Walter (Max-Planck-Institut fuer Astronomie) and Axel Weiss (Max-Planck-Institut fuer Radioastronomie). For details, see http://www.astro.dur.ac.uk/~irs/LESS
THE EUROPEAN WEEK OF ASTRONOMY AND SPACE SCIENCE
More than 1000 astronomers and space scientists will gather at the University of Hertfordshire for the European Week of Astronomy and Space Science (EWASS), incorporating the 2009 Royal Astronomical Society National Astronomy Meeting (NAM 2009) and the European Astronomical Society Joint Meeting (JENAM 2009). The meeting runs from 20th to 23rd April 2009.
EWASS is held in conjunction with the UK Solar Physics (UKSP) and Magnetosphere Ionosphere and Solar-Terrestrial Physics (MIST) meetings. The conference includes scientific sessions organised by the European Organisation for Astronomical Research in the Southern Hemisphere (ESO) and the European Space Agency (ESA).
EWASS is principally sponsored by the Royal Astronomical Society (RAS), the Science and Technology Facilities Council (STFC) and the University of Hertfordshire, Hatfield.
THE ROYAL ASTRONOMICAL SOCIETY
The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. The RAS organizes scientific meetings, publishes international research and review journals, recognizes outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 3000 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.