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

K. Kikuchi·C. Itoh·A. Kushino·T. Furusho·K. Matsushita·N. Y. Yamasaki·T. Ohashi·Y. Fukazawa·Y. Ikebe·H. Boehringer·H. Matsumoto
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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. = $9^\circ18'$ (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 $V n k T \sim 10^{60}$ 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$^{-1}$.

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K. Kikuchi, C. Itoh, A. Kushino, T. Furusho, K. Matsushita, N. Y. Yamasaki, T. Ohashi, Y. Fukazawa, Y. Ikebe, H. Boehringer, H. Matsumoto. 2000-01-18. Detection of an X-Ray Hot Region in the Virgo Cluster of Galaxies with ASCA. https://doi.org/10.1086/312535

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