论文标题
是什么设定了暗物质光环的飞溅半径：积聚历史或其他属性？
What sets the splashback radius of dark matter haloes: accretion history or other properties?
论文作者
论文摘要
暗物质光环的密度曲线包含有关其生长历史和物理特性的丰富信息。一个特别有趣的区域是飞溅半径，$ r _ {\ rm sp} $，它标志着光环中绕的粒子与经历了第一个输入的粒子之间的过渡。虽然$ r _ {\ rm sp} $对最近的积聚率的依赖性良好且理论上是预期的，但尚不清楚积分历史记录的哪些部分$ r _ {\ rm sp} $响应哪些零件，而其他晕圈属性可能会影响其位置。我们通过将一组模拟光环的动态测量的飞溅半径与其个体生长历史以及它们的结构，动力学和环境特性相关联，全面研究了这些问题。我们发现$ r _ {\ rm sp} $在一个交叉时间内对积聚敏感，但对先前的历史不敏感（与浓度相比，探测早期的时代）。所有次级相关性都弱得多，但是我们在较小，较旧，更椭圆形和更潮汐变形的光环中辨别出相对较高的$ r _ {\ rm sp} $。尽管有这些很小的影响，但我们得出的结论是，飞溅半径是过去动态时期内光晕增长的清晰指标。我们预测，幅度差距应该是光环的积聚率和飞溅半径的有前途的可观察指标。
The density profiles of dark matter haloes contain rich information about their growth history and physical properties. One particularly interesting region is the splashback radius, $R_{\rm sp}$, which marks the transition between particles orbiting in the halo and particles undergoing first infall. While the dependence of $R_{\rm sp}$ on the recent accretion rate is well established and theoretically expected, it is not clear exactly what parts of the accretion history $R_{\rm sp}$ responds to, and what other halo properties might additionally influence its position. We comprehensively investigate these questions by correlating the dynamically measured splashback radii of a large set of simulated haloes with their individual growth histories as well as their structural, dynamical, and environmental properties. We find that $R_{\rm sp}$ is sensitive to the accretion over one crossing time but largely insensitive to the prior history (in contrast to concentration, which probes earlier epochs). All secondary correlations are much weaker, but we discern a relatively higher $R_{\rm sp}$ in less massive, older, more elliptical, and more tidally deformed haloes. Despite these minor influences, we conclude that the splashback radius is a clean indicator of a halo's growth over the past dynamical time. We predict that the magnitude gap should be a promising observable indicator of a halo's accretion rate and splashback radius.
