Lopsided Satellite Distributions around Isolated Host Galaxies in a ΛCDM Universe
Lopsided Satellite Distributions around Isolated Host Galaxies in a ΛCDM Universe
复制标题
DOI：
10.3847/1538-4357/acc069
复制
发表时间：
2023-03
期刊：
影响因子：
--
通讯作者：
Adam Samuels;T. Brainerd
中科院分区：
文献类型：
--
作者：
Adam Samuels;T. Brainerd
最近的一项观测研究发现，明亮的孤立宿主星系的卫星的投影空间分布相对于宿主星系的位置往往是不平衡的。在这里，我们研究了大量明亮的，孤立的宿主星系，从模拟红移调查的Λ-冷暗物质（ΛCDM）模拟卫星的空间分布。宿主星系及其卫星是使用与观测研究中使用的标准相同的选择标准确定的，从而可以直接比较模拟和观测系统的结果。为了表征卫星的空间分布，我们采用了两个统计量：（1）卫星的成对聚类和（2）平均合成长度。与观测研究一致，我们发现模拟中的卫星有强烈的倾向位于其主机的同一侧，并且蓝色主机的卫星信号最明显。这些不平衡的卫星分布不仅仅是由于观测到的卫星目录不完整或存在被错误地识别为卫星的物体。此外，在遥远的过去（2008年）加入其宿主晕的卫星在其空间分布中显示出明显的不平衡性，因此，不平衡性不仅仅归因于卫星的晚期吸积。
A recent observational study found that the projected spatial distributions of the satellites of bright, isolated host galaxies tend to be lopsided with respect to the locations of the hosts. Here, we examine the spatial distributions of the satellites of a large number of bright, isolated host galaxies that were obtained from mock redshift surveys of a Λ-cold dark matter (ΛCDM) simulation. Host galaxies and their satellites were identified using selection criteria that are identical to those used in the observational study, allowing for a direct comparison of the results for the simulated and observed systems. To characterize the spatial distribution of the satellites, we adopt two statistics: (1) the pairwise clustering of the satellites and (2) the mean resultant length. In agreement with the observational study, we find a strong tendency for satellites in the simulation to be located on the same side of their host, and the signal is most pronounced for the satellites of blue hosts. These lopsided satellite distributions are not solely attributable to incompleteness of the observed satellite catalog or the presence of objects that have been falsely identified as satellites. In addition, satellites that joined their hosts’ halos in the distant past (≳8 Gyr) show a pronounced lopsidedness in their spatial distributions and, therefore, the lopsidedness is not solely attributable to the late-time accretion of satellites.