AI 中文总结
该研究通过N体模拟发现，带小尺度等曲率扰动的超轻暗物质可在小暗晕中心主导，为解释星系中心多样性提供了可能途径。
AI 中文摘要
观测到的星系中心多样性促使人们提出，不同星系的局部暗物质组成可能存在差异。然而，在传统的多组分暗物质场景中，相对丰度的大幅随机变化并不常见，冷组分通常保持主导地位。我们开展了N体模拟，模拟对象包含占次要地位的超轻暗物质组分，该组分带有显著的大幅小尺度等曲率扰动。我们发现，尽管非线性演化在星系尺度上很大程度上使超轻暗物质的比例均匀化，但超轻暗物质仍可能在小暗晕的中心增强，甚至占据主导，因为初始的大幅超轻暗物质波动会形成早期势阱，这些势阱后来会形成暗晕中心。即使宇宙学中超轻暗物质的比例低于O(10%)，超轻暗物质主导的区域也能延伸至0.01R_vir之外，占中心暗物质密度的一半以上。这种中心分离为随机尖峰-核多样性提供了可能的途径，有望解释观测到的星系中心多样性。
英文摘要
The observed diversity of galaxy centers motivates the possibility that the local dark matter composition may vary among galaxies. In conventional multicomponent dark matter scenarios, however, large stochastic variations in the relative abundances are not generically expected, with the cold component typically remaining dominant. We perform $N$-body simulations with a subdominant ultralight dark matter component carrying significant large-amplitude small-scale isocurvature perturbations. We find that although nonlinear evolution largely homogenizes its fraction on galactic scales,ultralight dark matter can still be enhanced and even dominate the centers of small halos because large initial ultralight dark matter fluctuations seed early potential wells that later form halo centers. The ultralight-dominated region can extend beyond $0.01R_{\rm vir}$ and account for more than half of the central dark matter density, even for a cosmological ultralight dark matter fraction below $O(10\%)$. This central segregation provides a possible route to stochastic cusp--core diversity, potentially explaining the observed diversity of galaxy centers.
Comments25 pages and 10 figures
