Discovery of Gas Bulk Motion in the Galaxy Cluster Abell 2256 with Suzaku
Discovery of Gas Bulk Motion in the Galaxy Cluster Abell 2256 with Suzaku
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DOI：
10.1093/pasj/63.sp3.s1009
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发表时间：
2011-04
影响因子：
2.3
通讯作者：
T. Tamura;K. Hayashida;S. Ueda;Masaaki Nagai
中科院分区：
文献类型：
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作者：
T. Tamura;K. Hayashida;S. Ueda;Masaaki Nagai
给出了Suzaku对星系团Abell2256的观测结果。这个星系团是一个典型的、经过充分研究的合并系统，在X射线表面亮度和成员星系的径向速度分布上都显示出亚结构。天空中有主分量和次分量，间隔为3‘.5，成员星系的径向速度峰距S约2000公里。为了用Suzaku Xis测量这两种气体组分的铁K壳线的多普勒频移，对仪器的能量标度进行了仔细的评估，发现校准得很好。检测到亚组分气体的径向速度相对于主团簇的径向速度发生了显著的偏移。所有三个XIS传感器都独立且一致地显示了这三个传感器之间的变化。差额为1500元/分300元(统计)元300元/分(系统)公里S元^-1}元。X射线确定了星系的绝对红移，因此主成分和子成分之间的差异在光学上与成员星系的差异是一致的。观测有力地表明，发出X射线的气体正在作为星系团内的一个子结构与星系一起移动。这些结果与其他关于合并星系团中气体整体运动的X射线观测结果一起进行了讨论。
The results from Suzaku observations of the galaxy cluster Abell2256 are presented. This cluster is a prototypical and well-studied merging system, exhibiting substructures both in the X-ray surface brightness and in the radial velocity distribution of member galaxies. There are main and sub components separating by 3'.5 in the sky and by about 2000 km s$^{-1}$ in radial velocity peaks of member galaxies. In order to measure Doppler shifts of iron K-shell lines from the two gas components by the Suzaku XIS, the energy scale of the instrument was evaluated carefully and found to be calibrated well. A significant shift of the radial velocity of the sub component gas with respect to that of the main cluster was detected. All three XIS sensors show the shift independently and consistently among the three. The difference is found to be 1500 $\pm 300$ (statistical) $\pm 300$ (systematic) km s$^{-1}$. The X-ray determined absolute redshifts of and hence the difference between the main and sub components are consistent with those of member galaxies in optical. The observation indicates robustly that the X-ray emitting gas is moving together with galaxies as a substructure within the cluster. These results along with other X-ray observations of gas bulk motions in merging clusters are discussed.