Building a representative sample of local galaxy groups

Galaxy groups are ideal systems to study baryon physics, which is important forboth using clusters for precision cosmology and understanding galaxy formationand evolution. Over the last decade, our understanding on the ICM properties ofgalaxy groups has been greatly improved. However, there is no a representativegroup sample with Chandra or XMM that allows full coverage to r_500. We havedefined such a sample of 13 galaxy groups that also takes advantage of theexisting Chandra and XMM data. They are purely Xray luminosity selected fromthe 400 deg^2 survey. We propose to observe the lowL_X bin in this cycle tostart the project. The final sample can also be combined with the REXCESS sampleto extend its luminosity threshold by a factor of ten. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]