具有罕见和频繁自相互作用的暗物质晕的不等质量合并
Unequal-mass mergers of dark matter haloes with rare and frequent self-interactions
摘要：
暗物质（DM）的自相互作用被提出来解决标准冷DM宇宙学中的小尺度问题。在这里，我们研究DM自相互作用在星系和星系团合并系统中的作用。我们进行N体DM的理想化设置的模拟研究DM的自相互作用是弹性和速度无关的影响。我们超越了普遍采用的假设大角度（罕见）DM散射，注意小角度（频繁）散射对天体物理观测和相关量的影响。具体来说，我们专注于DM-星系偏移，星系-星系距离，晕的形状，形态，和相位-空间分布。此外，我们比较了两种方法来识别峰值：一种是基于重力势，一种是基于等密度线。我们发现，结果是敏感的峰值发现的方法，这对合并系统的模拟和观察，特别是对小合并的分析提出了挑战。大的DM-星系偏移可以发生在较小的合并中，特别是在频繁的自相互作用中。在这些情况下，次晕倾向于迅速溶解。虽然集群在合并后期阶段导致罕见的和频繁的散射之间的潜在的巨大差异，我们认为，这些差异是从观察中提取的非平凡的。因此，我们研究的星系/恒星的人口仍然不同，即使在DM晕合并。我们发现，这些无碰撞示踪剂的行为不同的罕见和频繁的散射，潜在地提供了一个手柄来了解DM的微观物理。
英文摘要：
Dark matter (DM) self-interactions have been proposed to solve problems on small length scales within the standard cold DM cosmology. Here, we investigate the effects of DM self-interactions in merging systems of galaxies and galaxy clusters with equal and unequal mass ratios. We perform N-body DM-only simulations of idealized setups to study the effects of DM self-interactions that are elastic and velocity-independent. We go beyond the commonly adopted assumption of large-angle (rare) DM scatterings, paying attention to the impact of small-angle (frequent) scatterings on astrophysical observables and related quantities. Specifically, we focus on DM-galaxy offsets, galaxy--galaxy distances, halo shapes, morphology, and the phase--space distribution. Moreover, we compare two methods to identify peaks: one based on the gravitational potential and one based on isodensity contours. We find that the results are sensitive to the peak finding method, which poses a challenge for the analysis of merging systems in simulations and observations, especially for minor mergers. Large DM-galaxy offsets can occur in minor mergers, especially with frequent self-interactions. The subhalo tends to dissolve quickly for these cases. While clusters in late merger phases lead to potentially large differences between rare and frequent scatterings, we believe that these differences are non-trivial to extract from observations. We therefore study the galaxy/star populations which remain distinct even after the DM haloes have coalesced. We find that these collisionless tracers behave differently for rare and frequent scatterings, potentially giving a handle to learn about the micro-physics of DM.
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。
