论文标题
三百个项目：簇模拟中的后挡板星系
The Three Hundred Project: Backsplash galaxies in simulations of clusters
论文作者
论文摘要
在星系集群的外部区域，星系可能是第一次掉入群集，或者已经过去的某个时候已经穿过了群集中心。为了调查这两个不同的人群，我们利用了Thethreehuntred项目，该项目是324个对星系簇的流体动力复合的套件。特别是，我们研究星系的“后挡板人群”；那些在群集中心的$ r_ {200} $之内通过的那些人的历史记录中中心的那些人，但现在不在此半径之外。我们发现，平均在$ r_ {200} $和$ 2R_ {200} $之间的所有星系中，从$ z = 0 $中的$ 2R_ {200} $都是后板星系星系，但是该部分取决于集群的动态状态，因为动态放松的簇具有更大的后板压力。我们还发现，该人群主要是在最近开发的（$ z \ leq0.4 $），并且取决于集群的近期历史。最后，我们表明，可以根据群集的观察性能来预测给定群集的动态状态，因此可以预测其郊区的后挡板星系的比例。
In the outer regions of a galaxy cluster, galaxies may be either falling into the cluster for the first time, or have already passed through the cluster centre at some point in their past. To investigate these two distinct populations, we utilise TheThreeHundred project, a suite of 324 hydrodynamical resimulations of galaxy clusters. In particular, we study the 'backsplash population' of galaxies; those that have passed within $R_{200}$ of the cluster centre at some time in their history, but are now outside of this radius. We find that, on average, over half of all galaxies between $R_{200}$ and $2R_{200}$ from their host at $z=0$ are backsplash galaxies, but that this fraction is dependent on the dynamical state of a cluster, as dynamically relaxed clusters have a greater backsplash fraction. We also find that this population is mostly developed at recent times ($z\leq0.4$), and is dependent on the recent history of a cluster. Finally, we show that the dynamical state of a given cluster, and thus the fraction of backsplash galaxies in its outskirts, can be predicted based on observational properties of the cluster.
