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arXiv 1105.1397astro-ph.CO
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星系团中的星系子群

Galaxy subgroups in galaxy clusters

J. D. Cohn

摘要:

星系团作为同一个陨晕的一部分落入星系团中,由于它们有共同的起源,因此可以保持相关性。N-body模拟被用来研究星系团中这些星系亚群的性质,包括它们的丰度和普遍性。发现了大于等于8个星系的所有子群的大小、密度和速度色散,并与主星系团的大小、密度和速度色散进行了比较。最大的星系群提供了一个星系团中的首选方向,并与星系团中的其他首选方向进行比较。在集群质量测量(通过五个观测),沿~ 96视线的散射,比较视线的关系,这个首选的方向:在集群速度分散测量散射显示最强的相关性。Dressler-Shectman检验(Dressler & Shectman 1988)应用于这些聚类,以查看其识别的子结构是否与这些子组相关。任何特定视线的结果看起来都是嘈杂的;然而,具有较大子组的聚类往往具有较高的视线分数,其中测试检测到子结构。

英文摘要:

Galaxies which fall into clusters as part of the same infall halo can retain correlations due to their shared origin. N-body simulations are used to study properties of such galaxy subgroups within clusters, including their richnesses and prevalence. The sizes, densities and velocity dispersions of all subgroups with >= 8 galaxies are found and compared to those of the host clusters. The largest galaxy subgroup provides a preferred direction in the cluster and is compared to other preferred directions in the cluster. Scatter in cluster mass measurements (via five observables), along ~ 96 lines of sight, is compared to the relation of the line of sight to this preferred direction: scatter in cluster velocity dispersion measurements show the strongest correlation. The Dressler-Shectman test (Dressler & Shectman 1988), is applied to these clusters, to see whether the substructure it identifies is related to these subgroups. The results for any specific line of sight seem noisy; however, clusters with large subgroups tend to have a higher fraction of lines of sight where the test detects substructure.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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