一对近邻大质量早型星系的并合性质  

Merging properties of a pair of local massive early-type galaxies

作　　者：曹霄 郝彩娜[1] 郭蕊[1] 贺艳琴[1] CAO Xiao;HAO Caina;GUO Rui;HE Yanqin(Astrophysics Center,Tianjin Normal University,Tianjin 300387,China)

机构地区：[1]天津师范大学天体物理中心,天津300387

出　　处：《天津师范大学学报（自然科学版）》2020年第4期20-26,共7页Journal of Tianjin Normal University：Natural Science Edition

基　　金：国家自然科学基金资助项目(11733002)。

摘　　要：星系并合在星系的形成与演化中具有关键作用,利用深度曝光成像观测数据,研究了一对相互作用星系的并合性质以及其中一个星系壳状结构的起源.结果表明:壳状结构的g-i颜色较星系中心处蓝,多波段能谱分布显示壳状结构的u^*波段颜色较核心更蓝.这说明星族年龄更年轻或金属丰度更低,因此壳状结构来源于次并合,其所产生的壳状结构为主星系贡献了14.1%的恒星质量.2个星系各自整体的能谱分布表明它们的星族性质十分接近,结合中性氢的观测结果可知这对星系正在进行主干并合(major dry merger).通过对并合时标的估算得出在没有新的并合事件发生的情况下,这对星系将在~1.4 Gyr后并合成为1个恒星质量为~2×10^11M⊙的贫气体星系.Galaxy merging plays an important role in the formation and evolution of galaxies,the properties of a pair of local massive early-type galaxies and the origin of the shell feature of one galaxy in the pair was studied based on deep imaging data.The results show that the g-i color of the shell is bluer than that of the core region,and the multi-waveband spectral energy distribution of the shell shows an even bluer color in the u*band than the core region.This implies younger or more metal-poor stellar population properties of the shell,which suggests a minor merger origin of the shell.The shell contributes 14.1%of the total stellar mass of the main galaxy.The integrated spectral energy distributions of the two galaxies in the pair indicate their similar stellar population properties.In combination with the HI observations,it turns out that this pair of galaxies is in a major dry merger event.The estimated merging timescale suggests that they will merge into a metal-poor massive galaxy in^1.4 Gyr if no further merging events take place.

关 键 词：早型星系 星系演化 壳状结构 次并合 主并 

分 类 号：P157.9[天文地球—天文学]