Star formation quenching in simulated group and cluster galaxies: when, how, and why?
Star formation quenching in simulated group and cluster galaxies: when, how, and why?
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DOI：
10.1093/mnras/stu2293
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发表时间：
2014-10
影响因子：
4.8
通讯作者：
Y. Bahé;I. McCarthy
中科院分区：
文献类型：
--
作者：
Y. Bahé;I. McCarthy
观察到星星的形成被抑制在集团和星系团相比，该领域。为了深入了解淬火过程，我们分析了在GIMIC宇宙流体动力学模拟套件中形成的~2000个星系。猝灭的时间从吸积前的约2 Gyr（第一次穿越r200，c）到吸积后的>4 Gyr不等，取决于卫星和宿主的质量。一旦开始，在低质量星系（M* < 10^10 M_Sun）中，淬火是迅速的（>~ 500 Myr），但对于更大质量的卫星来说，淬火的时间要长得多。这些模拟预测了由冲压压力驱动的外流（而不是潮汐力）在从卫星星系中移除恒星形成的星际物质（ISM）方面的重要作用，特别是矮星（M* ~ 10^9 M_Sun），它们占了近三分之二的ISM损失。在猝灭完成之前，这一比例上升到约80%，即使是银河系类似物（M* ~ 10^10.5 M_Sun）在群（M_host ~ 10^13.5 M_Sun）中。我们表明，（i）ISM剥离是显着更有效的早期比在z = 0;（ii）大约一半的气体剥离从“银河喷泉”和一半直接从星星形成盘;（iii）星系经历剥离冲压压力高达100倍的平均在一个给定的组/集群中心半径，因为它们优先位于过密ICM地区。值得注意的是，剥离导致我们模拟卫星周围的扩展气体晕损失的最多一半。这些结果与目前的图片形成鲜明对比的扼杀-去除ISM通过星星形成后剥离的热晕-是占主导地位的机制淬火集团和集群卫星。
Star formation is observed to be suppressed in group and cluster galaxies compared to the field. To gain insight into the quenching process, we have analysed ~2000 galaxies formed in the GIMIC suite of cosmological hydrodynamical simulations. The time of quenching varies from ~2 Gyr before accretion (first crossing of r200,c) to >4 Gyr after, depending on satellite and host mass. Once begun, quenching is rapid (>~ 500 Myr) in low-mass galaxies (M* < 10^10 M_Sun), but significantly more protracted for more massive satellites. The simulations predict a substantial role of outflows driven by ram pressure -- but not tidal forces -- in removing the star-forming interstellar matter (ISM) from satellite galaxies, especially dwarfs (M* ~ 10^9 M_Sun) where they account for nearly two thirds of ISM loss in both groups and clusters. Immediately before quenching is complete, this fraction rises to ~80% even for Milky Way analogues (M* ~ 10^10.5 M_Sun) in groups (M_host ~ 10^13.5 M_Sun). We show that (i) ISM stripping was significantly more effective at early times than at z = 0; (ii) approximately half the gas is stripped from `galactic fountains' and half directly from the star forming disk; (iii) galaxies undergoing stripping experience ram pressure up to ~100 times the average at a given group/cluster-centric radius, because they are preferentially located in overdense ICM regions. Remarkably, stripping causes at most half the loss of the extended gas haloes surrounding our simulated satellites. These results contrast sharply with the current picture of strangulation -- removal of the ISM through star formation after stripping of the hot halo -- being the dominant mechanism quenching group and cluster satellites.