AI 中文总结
研究星系团内光与暗物质晕形状对应关系，用CDM和SIDM流体动力学模拟，测量轴比等并量化对应，发现SIDM中DM晕内区变圆与恒星形态解耦，表明CDM中形状对应关系在SIDM宇宙失效。
AI 中文摘要
星系团内光（ICL）被提议作为星系团中暗物质（DM）晕形状的发光示踪剂，近期观测研究和ΛCDM模拟表明这两个组件之间紧密对齐。我们使用来自TheThreeHundred项目的匹配冷暗物质（CDM）和自相互作用暗物质（SIDM，σDM/m = 0.1和0.5 cm² g⁻¹）流体动力学星系团模拟，测试这种对应关系在自相互作用暗物质宇宙学中是否成立。我们测量了DM晕和恒星（BCG + ICL）分布的三维轴比和主轴方向随半径的变化，并使用加权重叠系数量化空间对应关系。在SIDM模拟中，随着DM截面增加，DM晕在其内部区域变得明显更圆，而恒星分布在CDM和SIDM中都保持相同的拉长形态。这种解耦在两个重子物理模型和两个分辨率水平上都是稳健的，对于σDM/m = 0.5 cm² g⁻¹，在>5σ水平上被检测到。这是因为恒星形状由沿大尺度结构潮汐剥离卫星的吸积几何决定，在CDM和SIDM中相同，而在SIDM中，晕形状还额外响应局部自相互作用。因此，CDM中展示的ICL - DM形状对应关系在SIDM宇宙中失效。
英文摘要
The intracluster light (ICL) has been proposed as a luminous tracer of the dark matter (DM) halo shape in galaxy clusters, with recent observational studies and $Λ$CDM simulations suggesting close alignment between the two components. We test whether this correspondence holds in a self-interacting dark matter (SIDM) cosmology using matched CDM and SIDM ($σ_\mathrm{DM}/m = 0.1$ and $0.5\;\mathrm{cm^{2}\,g^{-1}}$) hydrodynamical cluster simulations from TheThreeHundred project. We measure 3D axis ratios and major-axis orientations as a function of radius for both the DM halo and the stellar (BCG+ICL) distribution, and quantify the spatial correspondence using the Weighted Overlap Coefficient. In the SIDM simulations, DM haloes become significantly rounder in their inner regions with increasing DM cross-section, while the stellar distribution retains the same elongated morphology in both CDM and SIDM. This decoupling is robust across two baryonic physics models and two resolution levels, and is detected at $>5σ$ for $σ_\mathrm{DM}/m = 0.5\;\mathrm{cm^{2}\,g^{-1}}$. It arises because the stellar shape is governed by the accretion geometry of tidally stripped satellites along the large-scale structure, which is identical in CDM and SIDM, whereas, in SIDM, halo shapes respond additionally to local self-interactions. The ICL-DM shape correspondence demonstrated in CDM therefore breaks down in an SIDM universe.
Comments8 pages, 3 figures. accepted for publication in MNRAS Letters
