COMA星系团的研究5．动力学问题讨论

Studies on the COMA Cluster 5.Dynamical Problems

本文利用Ｋｅｎｔ和Ｇｕｎｎ提供的ＣＯＭＡ团天区４１４个星系的视向速度资料，以及关于团成员的统计判别结果，对ＣＯＭＡ团进行了动力学方面的讨论，分析表明ＣＯＭＡ团不存在显著动力学效应的整体转动。利用Ｋｉｎｇ－Ｍｉｃｈｉｅ模型拟合得到ＣＯＭＡ团的核半径为５．＇２（相当于２１０ｋｐｃ，取Ｈ０＝５０ｋｍ·ｓ－１·Ｍｐｃ－１），特征速度弥散度为９３５ｋｍ·ｓ－１．从动力学模型的角度来看，ＣＯＭＡ团有较为明显的形态分层。有迹象表明团中心区域的次结构是存在的。

By using the list of redshifts for 414 galaxies in the region of the COMA cluster compiled,by Kent and Gunn,and the results of the statistical determination of membership of individual galaxies in the list,some dynamical problems for the COMA cluster are discussed,in this paper.After careful analyses,it is shown that the rotation of the COMA cluster as a whole has very little effect on the dynamics of the cluster.For H=50 km s-1(Mpc)-1,the best fitting with the King-Michie model gives a core radius of 210 kpc(5'.2),and the characteristic velocity dispersion of 935 km/s.The morphological segregation of velocity dispersion is demonstrated.Some evidence supports the existence of substructure in the central region of the cluster.