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arXiv · 0806.3747

Suzaku Observation of the Ophiuchus Galaxy Cluster: One of the Hottest Cool Core Clusters

Yutaka Fujita·Kiyoshi Hayashida·Masaaki Nagai·Susumu Inoue·Hironori Matsumoto·Nobuhiro Okabe·Thomas. H. Reiprich·Craig L. Sarazin·Motokazu Takizawa
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Abstract

We present the analysis of a Suzaku observation of the Ophiuchus galaxy cluster. We confirmed that the cluster has a cool core. While the temperature of the intracluster medium (ICM) decreases toward the center, the metal abundance increases. Except for the core (r<~50 kpc), the cluster is hot (~9-10 keV) and is almost isothermal for r<~1 Mpc; the latter contradicts a previous study. We do not detect the variation of the redshift of the ICM in the cluster; the upper limit of the velocity difference is 3000 km s^-1. The iron line ratios in X-ray spectra indicate that the ICM has reached the ionization equilibrium state. From these results, we conclude that the Ophiuchus cluster is not a major merger cluster but one of the hottest clusters with a cool core. We obtain the upper limit of non-thermal emission from the cluster, which is consistent with both the recent claimed detection with INTEGRAL and the recent upper limits with the Swift/BAT. If the cluster has bright non-thermal emission as suggested by the INTEGRAL measurement, it is probably not due to a recent major cluster merger.

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Yutaka Fujita, Kiyoshi Hayashida, Masaaki Nagai, Susumu Inoue, Hironori Matsumoto, Nobuhiro Okabe, Thomas. H. Reiprich, Craig L. Sarazin, Motokazu Takizawa. 2008-06-23. Suzaku Observation of the Ophiuchus Galaxy Cluster: One of the Hottest Cool Core Clusters. https://doi.org/10.1093/pasj%2F60.5.1133

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