Moderate Redshift X-ray Selected Groups of Galaxies

Recent ROSAT and ASCA observations of nearby groups of galaxies have providedconsiderable new insight into these cosmologically important systems. We propose to extend these Xray studies to moderate (z0.20.5) redshifts with an XMM study of a sample of ROSATselected systems. Our existing groundbasedspectroscopy program combined with upcoming Cycle 8 HST images will provide agood census of the galaxy populations in these groups. XMM imaging will allow us to map out the spatial distribution of the hot gas, while EPIC spectroscopy will provide a measurement of the intragroup gas temperature andmetallicity. Therefore, we will make the first mass determinations for thesesystems and study the evolution of the intragroup medium out to z0.5 truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]