Detection of an X-ray hot region in the Virgo Cluster of galaxies with ASCA

Based on mapping observations with ASCA, an unusual hot region with a spati al extent of 1 deg(2) was discovered between M87 and M49 at a center coordi nate of R.A. = 12(h)27(m)36(s) and decl. = 9 degrees 18' (J2000). The X-ray emission from the region has a 2-10 keV flux of 1 x 10(-11) ergs s(-1) cm( -2) and a temperature of kT greater than or similar to 4 keV, which is sign ificantly higher than that in the surrounding medium of similar to 2 keV. T he internal thermal energy in the hot region is estimated to be VnkT simila r to 10(60) ergs with a gas density of similar to 10(-4) cm(-3). A power-la w spectrum with a photon index of 1.7-2.3 is also allowed by the data. The hot region suggests there is an energy input due to a shock that is probabl y caused by the motion of the gas associated with M49, infalling toward the M87 cluster with a velocity greater than or similar to 1000 km s(-1).