The XMM Cluster Survey: The Dynamical State of XMMXCS J2215.9–1738 at z = 1.457
The XMM Cluster Survey: The Dynamical State of XMMXCS J2215.9–1738 at z = 1.457
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XMM 聚类调查：XMMXCS J2215.9–1738 在 z = 1.457 处的动态状态
DOI：
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发表时间：
2007
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通讯作者：
M. West
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作者：
M. Hilton;C. Collins;S. Stanford;C. Lidman;K. Dawson;M. Davidson;S. Kay;A. Liddle;R. Mann;C. Miller;R. Nichol;A. Romer;K. Sabirli;P. T. P. Viana;M. West
我们提出了目前已知的最遥远的X射线选择星系团XMMXCS J2215.9-1738在z = 1.457的新的光谱观测，获得的DEIMOS仪器在W。M.凯克天文台和ESO甚大望远镜上的FORS 2仪器。在星系团的维里半径范围内，根据星系团的X射线性质，我们将已知的光谱星系团成员增加到17个，并计算出星系团的视线速度色散为580 ± 140 km s-1。我们发现温和的证据表明，维里半径内的星系的速度分布偏离一个单一的高斯。我们发现J2215.9-1738的性质与局部X射线标度关系的自相似演化不一致，发现在给定X射线温度的情况下，该星系团是不亮的，并且星系团内的介质含有约2-3倍于星系团星系每单位质量的动能。这些结果也许可以解释，如果集群观察后，离轴合并。另外，通过超新星和/或活动星系核活动加热的团内介质，解释所观察到的局部X射线光度-温度关系的斜率，可能是负责。
We present new spectroscopic observations of the most distant X-ray-selected galaxy cluster currently known, XMMXCS J2215.9-1738 at z = 1.457, obtained with the DEIMOS instrument at the W. M. Keck Observatory and the FORS2 instrument on the ESO Very Large Telescope. Within the cluster virial radius, as estimated from the cluster X-ray properties, we increase the number of known spectroscopic cluster members to 17 objects, and calculate the line-of-sight velocity dispersion of the cluster to be 580 ± 140 km s-1. We find mild evidence that the velocity distribution of galaxies within the virial radius deviates from a single Gaussian. We show that the properties of J2215.9-1738 are inconsistent with self-similar evolution of local X-ray scaling relations, finding that the cluster is underluminous given its X-ray temperature, and that the intracluster medium contains ~2-3 times the kinetic energy per unit mass of the cluster galaxies. These results can perhaps be explained if the cluster is observed in the aftermath of an off-axis merger. Alternatively, heating of the intracluster medium through supernovae and/or active galactic nucleus activity, as is required to explain the observed slope of the local X-ray luminosity-temperature relation, may be responsible.