|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Giant filament structures give rare insight into galaxy clusterevolution (Forwarded)
ROYAL ASTRONOMICAL SOCIETY PRESS INFORMATION NOTE
Issued by RAS Communications Officers: Anita Heward Tel: +44 (0)1483-420904 AND Peter Bond Tel: +44 (0)1483-268672 Fax: +44 (0)1483-274047 National Astronomy Meeting Press Room (4 - 7 April only): Tel: +44 (0)116-229-7474 or 229-7475 or 252-3312 or 252-3531 Fax: +44 (0)116-252-3531 RAS Web site: http://www.ras.org.uk/ RAS National Astronomy Meeting web site: http://www.nam2006.le.ac.uk/index.shtml CONTACT DETAILS ARE LISTED AT THE END OF THIS RELEASE. EMBARGOED FOR 00:01 BST, WEDNESDAY, 5 APRIL 2006 Ref.: PN 06/20 (NAM13) GIANT FILAMENT STRUCTURES GIVE RARE INSIGHT INTO GALAXY CLUSTER EVOLUTION A new image of the centre of a cluster of galaxies has revealed massive filamentary structures that give a rare insight into the evolution of galaxy clusters. "The star forming regions in the cluster that we'd observed previously were just the tip of the iceberg. We've now observed filaments of gas streaming out from these regions that are approximately 490 thousand light years across. The gaseous trails mark the path of galaxies travelling at high speed through the cluster. The origin of these unique features is still a matter for debate, but we think the combined action of tidal forces among galaxies in the cluster and of ram-pressure by the ambient medium caused the galaxies to fragment and blast out the ionized gas," said Dr Luca Cortese, who is presenting the results at the Royal Astronomical Society's National Astronomy Meeting on 5th April. An international team, lead by Dr Cortese, studied the physical properties of a compact group that is falling towards the centre of a cluster of galaxies known as Abell1367 at a rate of 1700 km/s. The group, which was discovered in 2002, has the highest density of star forming objects ever observed in local clusters. It contains two giant galaxies, at least ten dwarf galaxies or extragalactic clouds of gas and over a billion solar masses of diffuse gas filaments. Scientists believe that clusters of galaxies are formed from the accretion of compact groups like the one observed in Abell 1367. Formation of clusters of galaxies peaked 5 billion years ago. Now the rate is at least three times lower and it will slow dramatically due to the effects of the acceleration of the Universe. The Abell 1367 group is particularly important as it is only 300 million light years from Earth -- 'local' in terms of the Universe -- and so the scientists can see the processes at work in unprecedented detail. Dr Cortese explains, "The physical processes seen here are typical of young clusters, found far away in space and a long time ago. To really understand what's going on, we need a close up view. This is the first time we have found an example of a galaxy group mid-way through its transformation that is close enough for us to have a really good look at the structures surrounding the galaxies." The results suggest that at least part of the changes to the structure of cluster galaxies that took place in earlier epochs happened very differently to ones observed in today's clusters. In today's clusters of galaxies, the galaxies are travelling faster than in the infalling groups, which means that gravitational interactions between galaxies happen much faster. The study was carried out using the Italian National Telescope Galileo in La Palma in April 2004 and February 2006. The results of this study are accepted for publication on Astronomy and Astrophysics IMAGES For images of the filament structures, see: http://goldmine.mib.infn.it/papers/preprocessing.html FURTHER INFORMATION This study has been undertaken in collaboration with: Prof. Giuseppe Gavazzi Universita' degli Studi di Milano-Bicocca, Italy Dott. Alessandro Boselli Laboratoire d'Astrophysique de Marseille, France Dott. Paolo Franzetti IASF-INAF Milano, Italy Prof. Robert Kennicutt Institute of Astronomy, Cambridge, UK Dott. Karen O'Neil NRAO, USA Dott. Shoko Sakai UCLA, USA Telescopio Nazionale Galileo (TNG) The Telescopio Nazionale Galileo (TNG), with a primary mirror of 3.58m, is the national facility of the Italian astronomical community. It is located at Roque de Los Muchachos Observatory on La Palma, Canary Islands, and is operated by the Italian National Institute of Astrophysics (INAF). TNG is equipped with 5 instruments which are permanently operating on its foci and offer a large variety of observing modes covering the optical and near infrared wavelength ranges and spanning from broad band imaging to high resolution spectroscopy. For more information, visit: http://www.tng.iac.es/info/whatstng.html NOTES FOR EDITORS Royal Astronomical Society's National Astronomy Meeting The 2006 RAS National Astronomy Meeting is hosted by the University of Leicester. It is sponsored by the Royal Astronomical Society, the UK Particle Physics and Astronomy Research Council (PPARC), the University of Leicester and the National Space Centre, Leicester. CONTACTS Dr Luca Cortese School of Physics and Astronomy Cardiff University 5, The Parade Cardiff CF24 3YB Tel. +44 (0)2920876992 Fax. +44 (0)2920874056 From Wednesday 5th until Thursday 6th April, Dr Cortese can be contacted via the NAM press office (see above). |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
The Gravitational Instability Cosmological Theory | Br Dan Izzo | Astronomy Misc | 0 | August 31st 04 02:35 AM |
A Chain Cluster: Witnessing the Formation of a Rich Galaxy Cluster7 Billion Years Ago (Forwarded) | Andrew Yee | Astronomy Misc | 0 | December 31st 03 05:52 AM |
UFO Activities from Biblical Times (Long Text) | Kazmer Ujvarosy | UK Astronomy | 3 | December 25th 03 10:41 PM |
UFO Activities from Biblical Times (LONG TEXT) | Kazmer Ujvarosy | SETI | 2 | December 25th 03 07:33 PM |
UFO Activities from Biblical Times | Kazmer Ujvarosy | Astronomy Misc | 0 | December 25th 03 05:21 AM |