The Birmingham-CfA cluster scaling Project – I. Gas fraction and the M-Tx relation
The Birmingham-CfA cluster scaling Project – I. Gas fraction and the M-Tx relation
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DOI：
10.1046/j.1365-8711.2003.06401.x
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发表时间：
2003-01
影响因子：
4.8
通讯作者：
A. Sanderson;T. Ponman;A. Finoguenov;E. Lloyd-Davies;UK M.MarkevitchU.Birmingham;Mpe;Cfa;U. Michigan;U. Illinois
中科院分区：
文献类型：
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作者：
A. Sanderson;T. Ponman;A. Finoguenov;E. Lloyd-Davies;UK M.MarkevitchU.Birmingham;Mpe;Cfa;U. Michigan;U. Illinois
我们收集了大量的病毒化系统样本，包括66个星系团、星群和椭圆星系，并获得了高质量的x射线数据。对于每个系统，我们都拟合了描述气体密度和温度随半径变化的分析剖面，并对中央气体冷却的影响进行了校正。本文对这些体系的标度特性进行了分析，重点讨论了气体分布和M - T - X关系。除了星团和星团之外，我们的样本还包括两个早期型星系，它们经过精心挑选，以避免星团或星团x射线辐射的污染。我们将这些天体的性质与那些质量更大的星系进行比较，发现星系大小的光晕和温度相似的星系群之间存在系统差异的证据。我们推导出R200内M - T - X关系的平均对数斜率为1.84±0.06，尽管有一些证据表明随着质量的减少，M - T - X关系逐渐变陡。我们使用另外两种计算平均温度的方法恢复了类似的斜率。在等温假设下重复分析，我们发现斜率变化很小，为1.89±0.04，但归一化增加了30%。相应的，在等温情况下，R200内的平均气体分数从（0.13±0.01）h−3/2 70变化到（0.11±0.01）h−3/2 70，较小的分数变化反映了热系统和冷系统之间的不同行为。0.3R200以内的气体分数与温度有很强的相关性。这反映了气体密度斜率参数β与温度之间的强烈（5.8σ）趋势，这在以前的工作中已经发现。这些发现被解释为自相似性从星系反馈过程中断裂的证据，活跃的星系核加热或可能的气体冷却。我们讨论了我们的结果在一个层次结构形成场景的背景下的含义。
We have assembled a large sample of virialized systems, comprising 66 galaxy clusters, groups and elliptical galaxies with high-quality X-ray data. To each system we have fitted analytical profiles describing the gas density and temperature variation with radius, corrected for the effects of central gas cooling. We present an analysis of the scaling properties of these systems and focus in this paper on the gas distribution and M‐T X relation. In addition to clusters and groups, our sample includes two early-type galaxies, carefully selected to avoid contamination from group or cluster X-ray emission. We compare the properties of these objects with those of more massive systems and find evidence for a systematic difference between galaxy-sized haloes and groups of a similar temperature. We derive a mean logarithmic slope of the M‐T X relation within R200 of 1.84 ± 0.06, although there is some evidence of a gradual steepening in the M‐T X relation, with decreasing mass. We recover a similar slope using two additional methods of calculating the mean temperature. Repeating the analysis with the assumption of isothermality, we find the slope changes only slightly, to 1.89 ± 0.04, but the normalization is increased by 30 per cent. Correspondingly, the mean gas fraction within R200 changes from (0.13 ± 0.01) h −3/2 70 to (0.11 ± 0.01) h −3/2 70 , for the isothermal case, with the smaller fractional change reflecting different behaviour between hot and cool systems. There is a strong correlation between the gas fraction within 0.3R200 and temperature. This reflects the strong (5.8σ ) trend between the gas density slope parameter, β, and temperature, which has been found in previous work. These findings are interpreted as evidence for self-similarity breaking from galaxy feedback processes, active galactic nuclei heating or possibly gas cooling. We discuss the implications of our results in the context of a hierarchical structure formation scenario.