新成员和郊区居民可以驱动星系团中早型星系的大小-恒星质量关系的演化
Newcomers and suburbanites can drive the evolution of the size-stellar mass relation of early type galaxies in galaxy clusters
摘要：
在固定恒星质量$M_*$的情况下，平均而言，星系团中的大质量卫星早型星系（ETG）的有效半径$R_{\rm e}$在较低的红移处较大。我们使用最先进的宇宙学模拟IllustrisTNG 100从理论上研究了这种尺寸演化：我们在红移$z=0$处对$75$模拟的卫星ETG进行了采样，其中$M_* \ge 10^{10.4} M_{\odot}$属于模拟的两个最大质量（$\approx 10^{14.6} M_{\odot} $）晕。我们追溯了这两个星系团的主要祖先，并在$z>0$上选择了它们的卫星ETG，所采用的标准与$z=0$相同。模拟的星团卫星ETGs的$R_{\rm e}-M_*$关系，这是稳健的测量出$z=0.85$，演变类似的观测关系在红移范围$0\lesssim z \lesssim 0.85$。在模拟中，这种演化的主要驱动力是星系团获得新星系（“新成员”），以及位于$z=0.85$的大星系团中心距离（“郊区”）的成员星系的转变，最终成为$z=0$的大质量卫星ETG。虽然几个物理过程有助于改变人口的卫星ETG在考虑的红移间隔，模拟集群ETG的恒星质量函数的形状是没有显着不同的$z=0.85$和$z=0$，与观测一致。
英文摘要：
At fixed stellar mass $M_*$, the effective radius $R_{\rm e}$ of massive satellite early-type galaxies (ETGs) in galaxy clusters is, on average, larger at lower redshift. We study theoretically this size evolution using the state-of-the-art cosmological simulation IllustrisTNG100: we sampled $75$ simulated satellite ETGs at redshift $z=0$ with $M_* \ge 10^{10.4} M_{\odot}$ belonging to the two most massive ($\approx 10^{14.6} M_{\odot} $) haloes of the simulation. We traced back in time the two clusters' main progenitors and we selected their satellite ETGs at $z>0$ with the same criterion adopted at $z=0$. The $R_{\rm e}-M_*$ relation of the simulated cluster satellite ETGs, which is robustly measured out to $z=0.85$, evolves similarly to the observed relation over the redshift range $0\lesssim z \lesssim 0.85$. In the simulation the main drivers of this evolution are the acquisition of new galaxies ("newcomers") by the clusters and the transformation of member galaxies located at large clustercentric distance ("suburbanites") at $z=0.85$, which end up being massive satellite ETGs at $z=0$. Though several physical processes contribute to change the population of satellite ETGs in the considered redshift interval, the shape of the stellar mass function of the simulated cluster ETGs is not significantly different at $z=0.85$ and at $z=0$, consistent with observations.
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