星系团Abell 2199的恒星形成性质

The Star Formation Properties of Galaxy Cluster Abell 2199

通过对近邻星系团Abell 2199中290颗成员星系进行形态分类,研究这些星系的恒星形成率及其与形态和相关物理特性之间的关系.该星系团中星系的特征恒星形成率与Hα等值宽度、星系光谱在4000(?)处的跃变程度以及星系所包含的恒星质量之间有较强的相关性.这些星系的恒星形成活动没有表现出明显的环境效应,表明该星系团仍处在剧烈的动力学演化阶段,远没有达到动力学平衡.

Based on the morphological classification for 290 member galaxies in the neaby galaxy cluster Abell 2199,relations of the star formation rates(SFRs)with morphology and relevant physical properties of cluster galaxies are studied.A tight cor- relation between the SFR normalized by stellar mass(SFR/M.)and the H_αequivalent width is found.The correlations of SFR/M.with the continuum break strength at 4000(?)and stellar mass(M.)are also confirmed.Recent finding of a significant sub- structure near the central cD galaxy indicates Abell 2199 possesses a group merger. These cluster galaxies show no significant environmental effect in their star formation activities,which suggests that Abell 2199 is still at an active stage of dynamical evolu- tion,far from a state of dynamical equilibrium.