Temperature Map and Iron Abundance of the Ophiuchus Cluster of Galaxies

Abstract

Abstract We present an X-ray surface-brightness distribution and a temperature map of the Ophiuchus cluster of galaxies observed by ASCA. The Ophiuchus cluster is a nearby rich cluster located at $ z= 0.028$ having an angular extent of $\sim 1 {{}^{\circ }}$. The observations were made by five pointings that cover the whole cluster. After deconvolution with the ASCA complex response function, we obtained the surface-brightness distribution with an angular resolution of $ {2{}^{\mathrm {\prime }}}$ and a temperature map with $ {8{}^{\mathrm {\prime }}}$ resolution. The X-ray surface-brightness distribution shows a nearly spherically symmetric distribution, except for a $ 15\sigma$ image excess at the position of $ {10{}^{\mathrm {\prime }}}$ to the north of the cluster center. On the other hand, a hot region with a temperature $ > 13 \,\mathrm{keV}$ is spread over a region of $ {20{}^{\mathrm {\prime }}}\times {30{}^{\mathrm {\prime }}}$ at $ {20{}^{\mathrm {\prime }}}$ to the west of the cluster center. Because these characteristics are similar to those of the Coma cluster, we conclude this cluster has never relaxed dynamically, and is also recently experienced a merger.