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Group Evolution Multiwavelength Study

The GEMS project is a collaboration involving groups at Swinburne, Birmingham, Nottingham, Liverpool John Moores Universities and the Institut d'Astrophysique de Paris. Our aim is to combine data taken in a variety of wavebands (currently X-ray, optical, near-infrared, and neutral hydrogen) with simulations, to study the properties of galaxy groups and the galaxies within them.

Galaxy groups are important astrophysical objects because the paradigm of hierarchical structure formation leads us to expect that clusters of galaxies are built up from the accretion and merger of smaller structures like galaxy groups. Observations suggest that the properties of galaxies strongly depend on the density of the environment in which they currently reside. They also suggest that most galaxies in the Universe are located in groups. However, due to the greater effort required to observe groups, this environment is understudied with respect to the significantly denser, but rarer, galaxy clusters.

It is the intention of this work to assemble the largest sample of galaxy groups for which a detailed X-ray analysis could feasibly be performed. Comparing the multi-wavelength properties of galaxy groups and their constituent galaxies with cosmological simulations and evolutionary models for such a large sample will improve our understanding of the way in which galaxies evolve within the environment in which they are most commonly found.

This sample of groups is publicly available. The selection of the sample and links to more information regarding the GEMS team and our group sample, are available on the left-hand side of this page.

This site is currently maintained by Sarah Brough, and was Last modified: Wed Oct 25 12:00:17 EST 2006