Very few galaxies can be considered isolated, as nearly all live in some form of a quasi-virialized group environment, from low-mass systems such as the Milky Way, surrounded by the Magellanic Clouds and the dwarf spheroidals, to the very massive but rare rich clusters of galaxies.
Our aim is to bring together a rich group of experts on galaxy groups, for which many questions are still unanswered, regarding both the groups as physical entities and the galaxy properties therein. Are groups of galaxies simply scaled-down clusters in terms of the properties of their hot, diffuse, X-ray emitting gas, or is the diffuse gas in groups more affected by AGN jets and supernova-driven galactic winds from the member galaxies than is the gas in clusters? How well do we know the selection functions of group samples? How accurately can we measure the masses of groups? How low can group masses be? Do we have a full view of the effects of the group global and local environments on the structural, morphological properties of galaxies as well as on their star formation histories (and quenching of ongoing star formation) and metal content, and can we point to the physical processes responsible (tidal and ram pressure stripping, galaxy mergers, turbulence)? Are group galaxies influenced by their outer filamentary environment? Do compact groups display properties (scaling relations at different wavelengths, morphological and kinematical disturbances, gas content, and star formation in galaxies) that are expected given their unusually high apparent densities? When do compact groups and fossil groups assemble their galaxies, do compact groups always turn into fossil groups and did all fossil groups go through a compact group phase? Do group and cluster scaling relations and the galaxy properties therein depend on magnitude gap? Are compact groups similar to the environments in which most galaxies evolved at high redshift?
These questions on groups are currently being answered through recent advances in both multi-wavelength observations (from radio to infrared to optical to X-rays), often with very large surveys (such as SDSS), as well as more theoretical work through simple modeling, semi-analytical modeling and hydrodynamical simulations. We intend to hear both communities present their results and show how the results depend on proper selection and modeling.
Scientific Organizing Committee |
Local Organizing Committee |
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UMR7095 - Institut d'Astrophysique de Paris - 98 bis boulevard Arago - 75014 Paris