发表机构
MIT; University of Copenhagen; Harvard University（麻省理工学院; 哥本哈根大学; 哈佛大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文通过N体模拟发现，重子成分使银河系大小SIDM晕的核心坍缩时标缩短约40倍，并导致恒星盘外翘，为暗物质研究提供新观测窗口。
AI 中文摘要
暗物质（DM）晕与其所承载的重子结构之间的引力耦合，是探究暗物质粒子本质的最有力窗口之一。自相互作用暗物质（SIDM）是对暗区的一种极简且动机良好的扩展，对星系及其晕的结构具有深远影响。然而，在银河系（MW）大小的星系中，重子对SIDM晕演化的影响以及由此产生的星系结构尚未得到充分探索。在本文中，我们证明，在银河系大小的星系中纳入重子成分，会导致在银河系寿命期内，对于低至$/sigma/m = 1 /，rm{cm}^2//rm{g}$的截面，加速的核心坍缩开始发生。我们展示了一系列冷暗物质和SIDM银河系大小星系的$N$体模拟，这些模拟有或没有重子成分，截面为$/sigma/m =[1.0, 2.5, 5.0]$ cm$^2$/g。我们在数值上和半解析上发现，恒星盘和核球的存在将仅含暗物质模拟中预测的核心坍缩时标缩短了约40倍。此外，由于核心坍缩在星系寿命期内开始，随后的密度增加增强了作用于恒星盘轨道的盘中面恢复力，导致盘面外翘。这项工作量化了重子与SIDM耦合的两个方向：重子加速了银河系大小晕中的核心坍缩，而由此产生的晕演化通过变薄和外翘重塑了盘面。这两个过程都为探测暗物质开辟了新的观测窗口。
英文摘要
The gravitational coupling between dark matter (DM) halos and the baryonic structures they host is one of the most powerful windows into the particle nature of DM. Self-interacting dark matter (SIDM) presents a minimal, well-motivated extension to the dark sector with dramatic consequences for the structure of galaxies and their halos. However, the impact of baryons on SIDM halo evolution and the resulting galactic structure has been underexplored in Milky Way (MW)-size galaxies. In this paper, we demonstrate that the inclusion of a baryonic component in a MW-size galaxy causes accelerated core collapse to begin within the MW's lifetime for a cross section as low as $σ/m = 1 \, \rm{cm}^2/\rm{g}$. We present a suite of $N$-body simulations of cold dark matter and SIDM MW-size galaxies with and without a baryonic component for cross sections $σ/m =[1.0, 2.5, 5.0]$ cm$^2$/g. We find numerically, and semi-analytically, that the presence of a stellar disk and bulge shortens the predicted core collapse timescales from the DM only simulations by a factor of $\sim 40$. Further, as the core collapse begins within the lifetime of the galaxy, the subsequent density increase strengthens the mid-plane restoring force exerted on stellar disk orbits, leading the disk to flare. This work quantifies both directions of the baryon--SIDM coupling: baryons accelerate core collapse in MW-sized halos, and the resulting halo evolution reshapes the disk through thinning and flaring. Both processes open new observational windows into DM.
Comments21 pages, 9 figures
