网站公告:

 2019全国中小学天文教师培训      北京师范大学天文系2019年优秀大学生夏令营



2015年 >> 返回 您当前所在位置:首页 > 科学研究 > 研究成果 > 2015年 > 正文

Identification of Galaxy Cluster Substructures with the Caustic Method

更新时间:2017-05-22 15:49:40点击次数:841次字号:T|T
Yu, H.; Serra, A. L.; Diaferio, A. & Baldi, M.

Abstract: We investigate the power of the caustic technique for identifying substructures of galaxy clusters from optical redshift data alone. The caustic technique is designed to estimate the mass profile of galaxy clusters to radii well beyond the virial radius, where dynamical equilibrium does not hold. Two by-products of this technique are the identification of the cluster members and the identification of the cluster substructures. We test the caustic technique as a substructure detector on two samples of 150 mock redshift surveys of clusters; the clusters are extracted from a large cosmological N-body simulation of a ΛCDM model and have masses of M 200 10 14 h -1 M ȯ andM 200 10 15 h -1 M ȯ in the two samples. We limit our analysis to substructures identified in the simulation with masses larger than10 13 h -1 M ȯ . With mockredshift surveys with 200 galaxies within 3R 200 , (1) the caustic technique recovers 30%–50% of the real substructures, and (2) 15%–20% of the substructures identified by the caustic technique correspond to real substructures of the central cluster, the remaining fraction being low-mass substructures, groups or substructures of clusters in the surrounding region, or chance alignments of unrelated galaxies. These encouraging results show that the caustic technique is a promising approach for investigating the complex dynamics of galaxy clusters.

The Astrophysical Journal, 2015 , 810 , 37 (编辑:admin)