Virgo Clusters At Redshift 0.35: Probing the Cluster-Group Transition

The cluster Xray luminositytemperature (LT) relationship is sensitive to cooling and feedback processes. Because L and T are used as surrogates for thecluster virial mass M in cosmological studies, understanding the LT and the LTM relationsincluding scatter and its evolution, is critical for cluster constraints on cosmological models, as well as models of galaxy and cluster evolution. We propose to measure T and L for a representative sample of 13 lowluminosity, lowT (22.6 keV) clusters of galaxies at moderate redshift (z0.320.37), from the ROSAT 160SD survey. We will study the LTM relation for 6 clusters with weak lensing masses obtained with HST. This study spans the massrange between rich clusters and groups, where feedback becomes important. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]