Galaxy evolution in groups and clusters: satellite star formation histories and quenching time-scales in a hierarchical Universe
Galaxy evolution in groups and clusters: satellite star formation histories and quenching time-scales in a hierarchical Universe
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DOI：
10.1093/mnras/stt469
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发表时间：
2012-06
影响因子：
4.8
通讯作者：
A. Wetzel;J. Tinker;C. Conroy;F. V. D. Bosch
中科院分区：
文献类型：
--
作者：
A. Wetzel;J. Tinker;C. Conroy;F. V. D. Bosch
星系团和星系团中的卫星星系比中心（场）星系更可能具有低的星星形成率（SFR）和位于红色序列上。利用SDSS DR 7的星系群/星系团星表，结合跟踪卫星轨道的宇宙学N体模拟，我们研究了z=0时大于5 × 10^9 M_sun的M_星星的星星形成历史和卫星的猝灭时标.我们首先探讨卫星坠落的历史：组预处理和弹射轨道是卫星演化的关键方面，并适当考虑这些，卫星坠落通常发生在z~0.5，或~5 Gyr前。为了获得准确的初始条件的卫星SFR在其首次落入的时间，我们构建了一个经验参数化的中央星系SFR和静止分数的演变。在此基础上，我们限制了随星猝灭的重要性和效率，发现随星猝灭是所有M_星星<10 ^10 M_太阳的静止星系形成的主要过程.然后，我们约束卫星星星形成的历史，发现一个“延迟，然后快速”淬火的情况下：卫星SFR演变不受影响的2-4 Gyr后，在此之后，星星形成淬火迅速，与e折叠时间< 0.8 Gyr。这些淬火时间尺度更短的大规模的卫星，但不依赖于主机晕质量：观察到的增加卫星静止分数与晕质量的出现仅仅是因为卫星淬火在一个较低的质量组之前的infall（组预处理），这是负责高达一半的淬火卫星在大规模集群。由于在猝灭开始之前有很长的时间延迟，卫星在坠落后经历了显着的恒星质量增长，几乎与中央星系相同。这一事实提供了关键的物理洞察下晕丰度匹配方法。
Satellite galaxies in groups and clusters are more likely to have low star formation rates (SFR) and lie on the red-sequence than central (field) galaxies. Using galaxy group/cluster catalogs from SDSS DR7, together with a cosmological N-body simulation to track satellite orbits, we examine the star formation histories and quenching timescales of satellites of M_star > 5 x 10^9 M_sun at z=0. We first explore satellite infall histories: group preprocessing and ejected orbits are critical aspects of satellite evolution, and properly accounting for these, satellite infall typically occurred at z~0.5, or ~5 Gyr ago. To obtain accurate initial conditions for the SFRs of satellites at their time of first infall, we construct an empirical parametrization for the evolution of central galaxy SFRs and quiescent fractions. With this, we constrain the importance and efficiency of satellite quenching as a function of satellite and host halo mass, finding that satellite quenching is the dominant process for building up all quiescent galaxies at M_star < 10^10 M_sun. We then constrain satellite star formation histories, finding a 'delayed-then-rapid' quenching scenario: satellite SFRs evolve unaffected for 2-4 Gyr after infall, after which star formation quenches rapidly, with an e-folding time of < 0.8 Gyr. These quenching timescales are shorter for more massive satellites but do not depend on host halo mass: the observed increase in satellite quiescent fraction with halo mass arises simply because of satellites quenching in a lower mass group prior to infall (group preprocessing), which is responsible for up to half of quenched satellites in massive clusters. Because of the long time delay before quenching starts, satellites experience significant stellar mass growth after infall, nearly identical to central galaxies. This fact provides key physical insight into the subhalo abundance matching method.