论文标题
从分析的角度来看,Baryons对暗物质Subhalos的潮汐剥离:磁盘令人震惊和与星星相遇
Tidal stripping of dark matter subhalos by baryons from analytical perspectives: disk shocking and encounters with stars
论文作者
论文摘要
冷暗物质(CDM)场景预测,银河系光环应比行星容纳大量的Subhalos,具体取决于暗物质的性质。预测它们的丰度和分布对暗物质搜索和对Subhalos本身的搜索具有重要意义,因为它们可以对CDM范式进行决定性测试。 Subhalo人口模型建设的一个主要困难是解释了Baryons引起的重力剥离,这对星系内部的整体动力学有很大影响。在本文中,我们从分析的角度将重点放在这些“重型”潮汐上,总结了关于银河磁盘令人震惊的先前工作,并彻底重新审视了与恒星相遇的影响。对于后者,我们超越了Gerhard and Fall(1983)的参考计算,以应对穿透性相遇并提供新的分析结果。基于对磁盘穿越过程中可能发生的多个恒星遇到的次荷兰能量变化的完整统计分析,我们表明Subhalos比$ \ sim 1 $ 〜M $ _ \ odot $轻,恒星相遇非常有效地修剪。这会在恒星环境中修改其质量功能。相比之下,磁盘令人震惊在修剪大规模的Subhalos方面更有效。简而言之,如果合理的弹性,Subhalos幸存的磁盘越过,除了内在的cuspy部分,潮汐质量功能与宇宙学强烈不同。如果脆弱,恒星遇到的数量密度仅在磁盘打击效果方面额外的数量级下降(例如,以银河系的方式在太阳位置处)。如我们所示,我们的结果可以纳入任何分析或数值亚何卢种群模型。这项研究补充了基于宇宙学模拟的人,这些模拟无法在如此小的尺度上解决暗物质Subhalos。
The cold dark matter (CDM) scenario predicts that galactic halos should host a huge amount of subhalos possibly lighter than planets, depending on the nature of dark matter. Predicting their abundance and distribution has important implications for dark matter searches and searches for subhalos themselves, as they could provide a decisive test of the CDM paradigm. A major difficulty in subhalo population model building is to account for the gravitational stripping induced by baryons, which strongly impact on the overall dynamics inside galaxies. In this paper, we focus on these "baryonic" tides from analytical perspectives, summarizing previous work on galactic disk shocking, and thoroughly revisiting the impact of individual encounters with stars. For the latter, we go beyond the reference calculation of Gerhard and Fall (1983) to deal with penetrative encounters, and provide new analytical results. Based upon a full statistical analysis of subhalo energy change during multiple stellar encounters possibly occurring during disk crossing, we show that subhalos lighter than $\sim 1$~M$_\odot$ are very efficiently pruned by stellar encounters. This modifies their mass function in a stellar environment. In contrast, disk shocking is more efficient at pruning massive subhalos. In short, if reasonably resilient, subhalos surviving disk crossing have lost all their mass but an inner cuspy part, with a tidal mass function strongly departing from the cosmological one. If fragile, stellar encounters make their number density drop by an additional order of magnitude with respect to disk-shocking effects only (e.g., at the solar position in the Milky Way). Our results can be incorporated to any analytical or numerical subhalo population model, as we show for illustration. This study complements those based on cosmological simulations, which cannot resolve dark matter subhalos on such small scales.