The Mass-Temperature Relation of 22 Nearby Clusters
The Mass-Temperature Relation of 22 Nearby Clusters
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DOI：
10.1086/320662
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发表时间：
2001-01
期刊：
影响因子：
--
通讯作者：
Haiguang Xu;G. Jin;Xiang-Ping Wu
中科院分区：
文献类型：
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作者：
Haiguang Xu;G. Jin;Xiang-Ping Wu
我们提出了一个新的调查的质量-温度（Mtot-TX）关系的22个附近的集群的基础上分析其ROSAT X射线表面亮度轮廓（SX）和ASCA发射加权温度。本文采用了两种估算星系团质量的方法，并对它们的结果进行了比较：（1）传统的气体分布的β模型，沿着等温和流体静力平衡假设;（2）暗物质分布的NFW剖面，其特征密度和长度由观测的SX（r）决定。这两个模型对SX（r）和类似的Mtot-TX关系产生了基本相同的拟合优度，后者显示出与Mtot-TX关系的简单引力标度的显著偏离。如果排除低温团簇（TX < 3.5 keV），则最佳拟合的Mtot-TX关系与理论预期一致，支持团簇形成早期团簇内介质预热的假设.与熵-温度分布一起，证实了星系团动力学标度关系在TX = 3-4 keV处存在相似性突变。
We present a new investigation of the mass-temperature (Mtot-TX) relation of 22 nearby clusters based on the analysis of their ROSAT X-ray surface brightness profiles (SX ) and their ASCA emission-weighted temperatures. Two methods of the cluster mass estimations are employed and their results are compared: (1) the conventional β-model for gas distribution along with the isothermal and hydrostatic equilibrium assumptions, and (2) the NFW profile for dark matter distribution whose characteristic density and length are determined by the observed SX(r). These two models yield essentially the same goodness of fits for SX(r) and the similar Mtot-TX relations, with the latter demonstrating a significant departure from the simple gravitational scaling of Mtot ∝ T. It is also shown that the best-fit Mtot-TX relations could be reconciled with the theoretical expectation if the low-temperature clusters (TX < 3.5 keV) are excluded from the list, which lends support to the scenario that the intracluster medium is preheated in the early phase of cluster formation. Together with the entropy-temperature distribution, the existence of a similarity break at TX = 3-4 keV in the dynamical scaling relations for galaxy clusters has been confirmed.