Detection of an X-Ray Hot Region in the Virgo Cluster of Galaxies with ASCA

Abstract

Based on mapping observations with ASCA, an unusual hot region with a spatial extent of 1 square degree was discovered between M87 and M49 at a center coordinate of R. A. = 12h 27m 36s and Dec. = $9^{\circ }18^{\prime }$ (J2000). The X-ray emission from the region has a 2-10 keV flux of $1\times 10^{-11}$ ergs s${}^{-1}$ cm${}^{-2}$ and a temperature of $kT\gtrsim 4$ keV, which is significantly higher than that in the surrounding medium of $\sim 2$ keV. The internal thermal energy in the hot region is estimated to be $VnkT\sim 10^{60}$ ergs with a gas density of $\sim 10^{-4}$ cm${}^{-3}$. A power-law spectrum with a photon index $1.7-2.3$ is also allowed by the data. The hot region suggests there is an energy input due to a shock which is probably caused by the motion of the gas associated with M49, infalling toward the M87 cluster with a velocity $\gtrsim 1000$ km s${}^{-1}$.

12 pages, 3 figures, accepted to ApJL

References in corpus (1)

• Nonthermal Bremsstrahlung and Hard X-ray Emission from Clusters of Galaxies

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