FOSSIL GROUPS - AN EMERGING CLASS OF MASS CONCENTRATIONS

Recent discoveries hint to the existence of a population of unusual massconcentrations called fossil groups. Their commonness is likely underestimateddue to biases in the optical and the reluctance to recognize new classes ofobjects. Proposed here are detailed observations of two new fossil groupsselected from a statistically complete Xray survey. We seek to confirm thegrouplike nature of the Xray emission thus validating their classification asfossil groups. With positive results we will place more stringent limits on thespatial density of these objects. We will measure accurate luminosities,temperatures, and mass profiles. This will facilitate a comparison to normalgroups and an investigation of the formation processes for fossil groups. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]