The Cluster of Galaxies Abell 970
The Cluster of Galaxies Abell 970
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Abell 970 星系团
DOI：
10.1051/0004-6361:20011134
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
P. Fouqué
中科院分区：
文献类型：
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作者：
L. Sodré;D. Proust;H. Capelato;G. L. Neto;H. Cuevas;H. Quintana;P. Fouqué
我们基于 ESO、Pic du Midi 和上普罗旺斯天文台测量的一组新的径向速度，对星系团 Abell 970 进行了动力学分析。我们的分析表明该团簇具有子结构并且失去了动态平衡。表面密度分布和X射线发射的峰值位置的差异以及星团中存在大尺度速度梯度的证据也支持了这一结论。我们还发现，用维里定理推断出的质量与用 X 射线发射推断出的质量之间存在差异，如果星系和星团内的气体不处于流体静力平衡，则这是可以预料到的。 Abell 970 具有适度的冷却流量，正如在不平衡时所预期的那样。我们认为冷却流可能具有间歇性行为，在星系团吸积到足以破坏星团中心动态平衡之后，大量冷却流的阶段之后是没有明显冷却流的阶段。在达到新的平衡后，将再次建立大量的冷却流。
We present a dynamical analysis of the galaxy cluster Abell 970 based on a new set of radial velocities measured at ESO, Pic du Midi and Haute-Provence observatories. Our analysis indicates that this cluster has a substructure and is out of dynamical equilibrium. This conclusion is also supported by differences in the positions of the peaks of the surface density distribution and X-ray emission, as well as by the evidence of a large-scale velocity gradient in the cluster. We also found a discrepancy between the masses inferred with the virial theorem and those inferred with the X-ray emission, which is expected if the galaxies and the gas inside the cluster are not in hydrostatic equilibrium. Abell 970 has a modest cooling flow, as is expected if it is out of equilibrium. We propose that cooling flows may have an intermittent behaviour, with phases of massive cooling flows being followed by phases without significant cooling flows after the accretion of a galaxy group massive enough to disrupt the dynamical equilibrium in the centre of the clusters. A massive cooling flow will be established again, after a new equilibrium is achieved.