MAGiiCAT VI. The Mg ii Intragroup Medium Is Kinematically Complex
MAGiiCAT VI. The Mg ii Intragroup Medium Is Kinematically Complex
复制标题
MAGiiCAT VI。
DOI：
10.3847/1538-4357/aaedbd
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
M. Murphy
中科院分区：
文献类型：
--
作者：
N. Nielsen;G. Kacprzak;S. Pointon;C. Churchill;M. Murphy
通过比较群环境和孤立星系环星系介质（CGM）中Mg ii的吸收，研究了环境对CGM的影响。如果在与背景类星体的投影距离D = 200kpc内，在吸收红移处有两个或两个以上的星系，且视距距离为500km s−1，则Mg ii吸收体与一个群有关。我们收集了由74个星系组成的29个星系群环境样本（每个星系群2到5个星系）。群吸收器的中位等效宽度（Å）和覆盖分数（）均大于孤立吸收器（分别为1.27σ和2.2σ），但柱中位密度在统计学上是一致的。像素速度两点相关函数分析表明，群体环境运动学与孤立环境（0.8σ）具有统计学上的可比性，但对于类似于流出运动的高速分散具有更大的威力。基团吸收器在较大的速度下显示更多的光学深度。一个由多个星系贡献观测气体的叠加模型与更大的等效宽度群吸收器相匹配，但由于成员星系之间的大速度分离，明显高估了运动学。最后，星系-星系群（成员星系光度相似）可能比星系-矮星系群（光度不同）具有更大的吸收体中值等效宽度（1.7σ）和速度色散（2.5σ）。我们认为，观测到的气体是与星系群而不是单个星系耦合在一起的，形成了一种星系群内部的介质。气体可能是由多个星系通过星系间转移的流出风或相互作用的成员的潮汐剥离沉积到这种介质中。
By comparing Mg ii absorption in the circumgalactic medium (CGM) of group environments to isolated galaxies, we investigated the impact of environment on the CGM. An Mg ii absorber is associated with a group if there are two or more galaxies at the absorption redshift within a projected distance of D = 200 kpc from a background quasar and a line-of-sight velocity separation of 500 km s−1. We compiled a sample of 29 group environments consisting of 74 galaxies (two to five galaxies per group) at . The group absorber median equivalent width ( Å) and covering fraction ( ) are larger than isolated absorbers (1.27σ and 2.2σ, respectively), but median column densities are statistically consistent. A pixel-velocity two-point correlation function analysis shows that group environment kinematics are statistically comparable to isolated environments (0.8σ), but with more power for high velocity dispersions similar to outflow kinematics. Group absorbers display more optical depth at larger velocities. A superposition model in which multiple galaxies contribute to the observed gas matches larger equivalent width group absorbers but significantly overpredicts the kinematics owing to large velocity separations between member galaxies. Finally, galaxy–galaxy groups (similar member galaxy luminosities) may have larger absorber median equivalent widths (1.7σ) and velocity dispersions (2.5σ) than galaxy–dwarf groups (disparate luminosities). We suggest that the observed gas is coupled to the group rather than individual galaxies, forming an intragroup medium. Gas may be deposited into this medium by multiple galaxies via outflowing winds undergoing an intergalactic transfer between member galaxies or from tidal stripping of interacting members.
影响因子：
4.8
作者：
Bielby, R.;Crighton, N. H. M.;Cantalupo, S.
通讯作者：
Cantalupo, S.