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arXiv 0712.2301astro-ph
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Sloan数字巡天和2dF星系红移巡天中星系团的星系轨道

Galaxy Orbits for Galaxy Clusters in Sloan Digital Sky Survey and 2dF Galaxy Redshift Survey

Ho Seong Hwang, Myung Gyoon Lee

摘要:

利用Sloan数字巡天(SDSS)和2dF星系红移巡天(2dFGRS)中的星系光谱样本,对星系团中的星系轨道进行了研究。利用星系的红移和位置数据,我们确定了这些巡天所涵盖的Abell星系团的成员星系。我们选择了10个星系团,使用三个标准:成员星系的数量大于或等于40,空间覆盖是完整的,和X射线质量分布在文献中。我们推导出径向配置文件的星系数密度和速度色散使用所有,早型,晚型星系为每个集群。我们利用Jeans方程研究了在星系团中心距离上具有等速和变速各向异性的样本星系团的星系轨道。使用所有成员星系,星系轨道被发现是各向同性的不确定性内的大多数样本星系团,虽然它是很难得出强有力的结论,由于大的误差和变化的函数的集群中心距离在计算的速度各向异性。我们研究了四个样本星系团的早型和晚型星系的轨道差异,发现它们之间没有显著差异。

英文摘要:

We present the results of a study for galaxy orbits in galaxy clusters using a spectroscopic sample of galaxies in Sloan Digital Sky Survey (SDSS) and 2dF Galaxy Redshift Survey (2dFGRS). We have determined the member galaxies of Abell clusters covered by these surveys using the galaxies' redshift and positional data. We have selected 10 clusters using three criteria: the number of member galaxies is greater than or equal to 40, the spatial coverage is complete, and X-ray mass profile is available in the literature. We derive the radial profile of the galaxy number density and velocity dispersion using all, early-type, and late-type galaxies for each cluster. We have investigated the galaxy orbits for our sample clusters with constant and variable velocity anisotropies over the clustercentric distance using Jeans equation. Using all member galaxies, the galaxy orbits are found to be isotropic within the uncertainty for most of sample clusters, although it is difficult to conclude strongly for some clusters due the large errors and the variation as a function of the clustercentric distance in the calculated velocity anisotropies. We investigated the orbital difference between early-type and late-type galaxies for four sample clusters, and found no significant difference between them.

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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