arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1206.3573astro-ph.CO
收藏

场Galerkin猝灭的恒星质量阈值

A Stellar Mass Threshold for Quenching of Field Galaxies

M. Geha, M. Blanton, R. Yan, J. Tinker

摘要:

我们证明了没有活跃恒星形成的矮星系(10^7 < M_stellar < 10^9 Msun)在该领域是极其罕见的(<0.06%)。我们的样本是基于美国宇航局斯隆地图集,这是一个重新分析斯隆数字天空调查数据发布8。我们研究了淬灭星系与恒星形成矮星系的相对数量,将淬灭星系定义为没有H α发射(EW_H α < 2 AA)和强烈的4000 AA-断裂。淬灭矮星系的比例随着与大质量宿主距离的增加而迅速减少,在超过1.5 Mpc的距离上趋于平稳。我们定义的星系超过1.5百万秒差距的一个巨大的宿主星系是在外地。我们证明了存在一个恒星质量阈值M_stellar <1.0 × 10^9 Msun,在此阈值以下,场中不存在淬灭星系。低于这个阈值,我们发现,没有2951场矮星系淬火,所有的场矮星系显示最近的恒星形成的证据。校正体积效应,这对应于淬火分数的1 σ上限为0.06%。在更稠密的环境中,在相同的恒星质量范围内,淬灭星系占矮星系总数的23%。大多数的淬灭矮星系(通常被归类为矮椭圆星系)都在大质量星系的2维里半径之内,只有百分之几的淬灭矮星系存在于4维里半径之外。因此,对于恒星质量小于1.0x10^9 Msun的星系,恒星形成的结束需要一个更大质量的邻居的存在,这对恒星形成反馈模型提供了严格的限制。

英文摘要:

We demonstrate that dwarf galaxies (10^7 < M_stellar < 10^9 Msun) with no active star formation are extremely rare (<0.06%) in the field. Our sample is based on the NASA-Sloan Atlas which is a re-analysis of the Sloan Digital Sky Survey Data Release 8. We examine the relative number of quenched versus star forming dwarf galaxies, defining quenched galaxies as having no Halpha emission (EW_Halpha < 2 AA) and a strong 4000AA-break. The fraction of quenched dwarf galaxies decreases rapidly with increasing distance from a massive host, leveling off for distances beyond 1.5 Mpc. We define galaxies beyond 1.5 Mpc of a massive host galaxy to be in the field. We demonstrate that there is a stellar mass threshold of M_stellar < 1.0x10^9 Msun below which quenched galaxies do not exist in the field. Below this threshold, we find that none of the 2951 field dwarf galaxies are quenched; all field dwarf galaxies show evidence for recent star formation. Correcting for volume effects, this corresponds to a 1-sigma upper limit on the quenched fraction of 0.06%. In more dense environments, quenched galaxies account for 23% of the dwarf population over the same stellar mass range. The majority of quenched dwarf galaxies (often classified as dwarf elliptical galaxies) are within 2 virial radii of a massive galaxy, and only a few percent of quenched dwarf galaxies exist beyond 4 virial radii. Thus, for galaxies with stellar mass less than 1.0x10^9 Msun, ending star-formation requires the presence of a more massive neighbor, providing a stringent constraint on models of star formation feedback.

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。

↑