Catching the Nearest Infalling Group in Motion with Chandra

Modern cosmology predicts that galaxy groups are continually being accreted onto clusters through a web-like network of filamentary structures. The M49 group resides just beyond the virial radius of Virgo, the nearest galaxy cluster, and is falling onto the cluster from the south. A region of elevated temperature has been detected with Suzaku between M49 and Virgo, suggesting a pre-merger shock associated with the infall of M49. We propose a 55 ksec Chandra follow up observation (1) to verify this shock candidate via identifying surface brightness discontinuity, (2) to fully exploit the Suzaku legacy program by resolving gaseous clumps and mitigating much of the cosmic X-ray background at the virial radius of Virgo, (3) and to study the distribution of intracluster X-ray binaries at cluster outskirts.