论文标题
Illustristng模拟中星系组和簇的协调组装
Coordinated Assembly of Galaxy Groups and Clusters in the IllustrisTNG Simulations
论文作者
论文摘要
最近对早期型星系光谱的恒星种群分析表明，集群中心的低质量星系具有较高的[$α/\ rm fe $]，并且大型星系的旧时代特征，与群集和田地外郊外的低质量星系人群不同。这种现象被称为“协调组装”，以强调这样一个事实，即大型集群中央星系的基础是从总体低质量星系人群的特殊子集中绘制的。在这里，我们在Illustristng模拟中探索了这个想法，尤其是TNG300运行，以了解环境，尤其是群集中心，以组和集群为单位（$ M_ {200C，z = 0} \ geq110^{13} {13} M_ {\ odot} $）。 Tracing histories of quenched satellite galaxies with $M_{\star,z=0}\geq10^{10} M_{\odot}$, we find that those in more massive dark matter halos, and located closer to the primary galaxies, are quenched earlier, have shorter star formation timescales, and older stellar ages.星形的时间表 - $ m _ {\ star} $和恒星年龄 - $ m _ {\ star} $缩放关系与观测非常吻合，并且预计与光晕质量和以集群为中心的距离有所不同。对环境的依赖性是由于卫星星系的插入历史引起的：位于$ z = 0 $的更大质量暗物质晕圈靠近集群中心的星系平均较早地积聚。在更大的光环中的星系中的星系较短，并取决于晕圈质量在其第一次积聚时的延迟，这表明群体预处理是卫星淬灭的重要方面。
Recent stellar population analysis of early-type galaxy spectra has demonstrated that the low-mass galaxies in cluster centers have high [$α/\rm Fe$] and old ages characteristic of massive galaxies and unlike the low-mass galaxy population in the outskirts of clusters and fields. This phenomenon has been termed "coordinated assembly" to highlight the fact that the building blocks of massive cluster central galaxies are drawn from a special subset of the overall low-mass galaxy population. Here we explore this idea in the IllustrisTNG simulations, particularly the TNG300 run, in order to understand how environment, especially cluster centers, shape the star formation histories of quiescent satellite galaxies in groups and clusters ($M_{200c,z=0}\geq10^{13} M_{\odot}$). Tracing histories of quenched satellite galaxies with $M_{\star,z=0}\geq10^{10} M_{\odot}$, we find that those in more massive dark matter halos, and located closer to the primary galaxies, are quenched earlier, have shorter star formation timescales, and older stellar ages. The star formation timescale-$M_{\star}$ and stellar age-$M_{\star}$ scaling relations are in good agreement with observations, and are predicted to vary with halo mass and cluster-centric distance. The dependence on environment arises due to the infall histories of satellite galaxies: galaxies that are located closer to cluster centers in more massive dark matter halos at $z=0$ were accreted earlier on average. The delay between infall and quenching time is shorter for galaxies in more massive halos, and depends on the halo mass at its first accretion, showing that group pre-processing is a crucial aspect in satellite quenching.
