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arXiv 1606.07810astro-ph.GA
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在压力下:通过剥离在低质量卫星星系团中淬灭恒星形成

Under Pressure: Quenching Star Formation in Low-Mass Satellite Galaxies via Stripping

Sean P. Fillingham, Michael C. Cooper, Andrew B. Pace, Michael Boylan-Kolchin, James S. Bullock, Shea Garrison-Kimmel, Coral Wheeler

摘要:

最近对本星系的研究,包括本星系群中的星系,发现环境(或卫星)猝灭的效率在卫星恒星质量低于~ $10^8\ {\rm M}_{\odot}$时急剧增加。这表明了一个物理尺度,其中淬灭在低质量下从缓慢的“饥饿”模式转变为快速的“剥离”模式。我们调查这种情况下使用观察到的HI表面密度分布的样本附近的66个星系作为输入的冲压压力和粘性剥离的分析计算的可扩展性。在广泛的主机属性,我们发现,剥离变得越来越有效,在$M_{*} < 10^{8-9}\ {\rm M}_{\odot}$,再现观察到的临界质量规模。然而,对于环银河系介质密度($n_{\rm halo} < 10^{-3.5}$ ${\rm cm}^{-3}$)的典型值,我们发现剥离并不完全有效;平均而言,坠落卫星的冷气库被剥离了< 40 - 70%,这不足以与观测结果相匹配。通过包括一个主机晕的气体分布,是cluerous,因此包含的区域的密度较高,我们能够重现所观察到的HI气体分数(从而高淬火分数和短淬火时标)的本地集团卫星,这表明主机晕cluerous气体淬火低质量系统在本地集团(和更大规模)主机晕可能是至关重要的。

英文摘要:

Recent studies of galaxies in the local Universe, including those in the Local Group, find that the efficiency of environmental (or satellite) quenching increases dramatically at satellite stellar masses below ~ $10^8\ {\rm M}_{\odot}$. This suggests a physical scale where quenching transitions from a slow "starvation" mode to a rapid "stripping" mode at low masses. We investigate the plausibility of this scenario using observed HI surface density profiles for a sample of 66 nearby galaxies as inputs to analytic calculations of ram-pressure and viscous stripping. Across a broad range of host properties, we find that stripping becomes increasingly effective at $M_{*} < 10^{8-9}\ {\rm M}_{\odot}$, reproducing the critical mass scale observed. However, for canonical values of the circumgalactic medium density ($n_{\rm halo} < 10^{-3.5}$ ${\rm cm}^{-3}$), we find that stripping is not fully effective; infalling satellites are, on average, stripped of < 40 - 70% of their cold gas reservoir, which is insufficient to match observations. By including a host halo gas distribution that is clumpy and therefore contains regions of higher density, we are able to reproduce the observed HI gas fractions (and thus the high quenched fraction and short quenching timescale) of Local Group satellites, suggesting that a host halo with clumpy gas may be crucial for quenching low-mass systems in Local Group-like (and more massive) host halos.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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