arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1407.6006astro-ph.GA
收藏

矮卫星星系猝灭的质量依赖性

The Mass Dependence of Dwarf Satellite Galaxy Quenching

Colin T. Slater, Eric F. Bell

摘要:

我们结合本集团的观测数据从美国宇航局-斯隆阿特拉斯显示淬火部分的卫星星系的变化,从低质量的矮椭球体和矮不规则更大规模的矮星类似的麦哲伦云。虽然几乎所有的低质量($M_\star \lesssim 10^7$ $M_\odot$)矮星都被淬灭,但在较高质量下,淬灭分数降低至约40- 50%。淬灭分数的这种变化很大,表明淬灭的有效性与卫星质量相关。我们将这一观测结果与卫星坠落和冲压压力剥离的模型相结合,表明低质量卫星必须在近心通道的1-2 Gyr内淬灭,以保持高淬灭分数,但更多的大质量矮星必须继续形成恒星,即使它们可能在>5 Gyr前落入它们的宿主。我们还描述了如何的敏感性的矮星冲压压力必须作为一个函数的质量,如果它是占淬火馏分的变化。虽然没有一个模型预测淬火有效性的先验,这个模型说明了物理要求,所观察到的淬火馏分上可能的淬火机制。

英文摘要:

We combine observations of the Local Group with data from the NASA-Sloan Atlas to show the variation in the quenched fraction of satellite galaxies from low mass dwarf spheroidals and dwarf irregulars to more massive dwarfs similar to the Magellanic clouds. While almost all of the low mass ($M_\star \lesssim 10^7$ $M_\odot$) dwarfs are quenched, at higher masses the quenched fraction decreases to approximately 40-50%. This change in the quenched fraction is large, and suggests a sudden change in the effectiveness of quenching that correlates with satellite mass. We combine this observation with models of satellite infall and ram pressure stripping to show that the low mass satellites must quench within 1-2 Gyr of pericenter passage to maintain a high quenched fraction, but that many more massive dwarfs must continue to form stars today even though they likely fell in to their host >5 Gyr ago. We also characterize how the susceptibility of dwarfs to ram pressure must vary as a function of mass if it is to account for the change in quenched fractions. Though neither model predicts the quenching effectiveness a priori, this modeling illustrates the physical requirements that the observed quenched fractions place on possible quenching mechanisms.

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。

↑