论文标题
将星系组积聚到星系簇中
Accretion of Galaxy Groups into Galaxy Clusters
论文作者
论文摘要
我们研究了$λ$ cdm中的组进口在星系簇的组装和动力学中的作用。我们从“宇宙学水动力学模拟”中选择了$ 10 $具有病毒质量$ m _ {\ rm 200} \ sim 10^{14} \，m _ {\ odot} $的簇，并跟随他们的星系，并使用其星系进行星系$ m _ {\ star} \ geq geq 1.5 \ geq 1.5 \ $ ______________ \ od。 $ \ sim 38 \％$的中位数$ z = 0 $作为小组的一部分积聚，并未直接从该领域中插入，尽管群集到群集散布了大量群集。这些星系协会的演变很快，其共同起源的观察性签名迅速以$ 1 $ -3 $ $ 3 $ gyr侵蚀，inflall后。在促进星系合并发生的条件下，即使在集群环境中也是如此。随着时间的推移，我们（按群集）平均识别出$ 17 \ pm 6 $的合并，其中发生在插入星系关联中，其中$ 7 \ pm 3 $出现在其群集宿主的病毒半径内。合并的数量显示出从集群到集群的大量分散，我们最庞大的系统的合并高于我们的大规模临界值42美元。 These mergers, which are typically gas rich for dwarfs and a combination of gas rich and gas poor for $M_{\star} \sim 10^{11} \, M_{\odot}$, may contribute significantly within $Λ$CDM to the formation of specific morphologies, such as lenticulars (S0) and blue compact dwarfs in groups and clusters.
We study the role of group infall in the assembly and dynamics of galaxy clusters in $Λ$CDM. We select $10$ clusters with virial mass $M_{\rm 200} \sim 10^{14} \, M_{\odot}$ from the cosmological hydrodynamical simulation Illustris and follow their galaxies with stellar mass $M_{\star} \geq 1.5 \times 10^8 \, M_{\odot}$. A median of $\sim 38\%$ of surviving galaxies at $z=0$ are accreted as part of groups and did not infall directly from the field, albeit with significant cluster-to-cluster scatter. The evolution of these galaxy associations is quick, with observational signatures of their common origin eroding rapidly in $1$-$3$ Gyr after infall. Substructure plays a dominant role in fostering the conditions for galaxy mergers to happen, even within the cluster environment. Integrated over time, we identify (per cluster) an average of $17 \pm 6$ mergers that occur in infalling galaxy associations, of which $7 \pm 3$ occur well within the virial radius of their cluster hosts. The number of mergers show large dispersion from cluster to cluster, with our most massive system having $42$ mergers above our mass cut-off. These mergers, which are typically gas rich for dwarfs and a combination of gas rich and gas poor for $M_{\star} \sim 10^{11} \, M_{\odot}$, may contribute significantly within $Λ$CDM to the formation of specific morphologies, such as lenticulars (S0) and blue compact dwarfs in groups and clusters.
