发表机构
Shanghai Astronomical Observatory; Tsung-Dao Lee Institute & School of Physics and Astronomy, Shanghai Jiao Tong University; Shanghai Key Laboratory for Particle Physics and Cosmology, and Key Laboratory for Particle Physics, Astrophysics and Cosmology Ministry of Education, Shanghai Jiao Tong University（上海天文台; 上海交通大学物理与天文学院、汤忠道研究院; 上海交通大学粒子物理与宇宙学上海市重点实验室、粒子物理、天体物理与宇宙学教育部重点实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用SDSS DR7与ELUCID模拟构建匹配空洞样本，测量多示踪剂质量偏差，发现质量比向空洞中心递减，揭示极端低密度区多示踪剂研究的统计局限性。
AI 中文摘要
宇宙空洞为研究低密度宇宙中星系、亚暗物质晕（subhalo）与暗物质的关系提供了独特环境。本研究利用SDSS星系星表与ELUCID约束模拟，建立了基于观测锚定的框架，用于测量匹配宇宙空洞内的多示踪剂质量偏差。研究构建了102个匹配空洞对样本，直接对比了本地宇宙观测约束实现下的星系、亚暗物质晕与暗物质质量分布。结果发现，星系-暗物质质量比和亚暗物质晕-暗物质质量比均向空洞中心递减，表明在最深的低密度区，发光物质与晕示踪剂相对于基础物质分布的耗竭程度不断加剧；而星系-亚暗物质晕质量比在空洞内区（$r/R_{\rm v}\leq0.5$）呈现出大得多的统计不确定性。通过对比独立与公共坐标系下的测量结果，研究表明坐标偏移会导致观测散差，但无法完全解释大不确定性；剩余不确定性主要源于空洞内部大质量亚暗物质晕（$\text{log}_{10}(M_{\rm sub}/h^{-1}M_\bigodot)\text{≥}11.8$）的严重匮乏，这大幅减少了空洞中心附近统计有效测量的数量。本研究结果提供了观测约束宇宙环境下多示踪剂质量偏差的直接测量，凸显了极端低密度区多示踪剂研究的基本统计局限性。
英文摘要
Cosmic voids provide a unique environment for studying the relationship between galaxies, subhaloes, and dark matter in the underdense Universe. Using the SDSS galaxy catalogue and the ELUCID constrained simulation, we establish an observationally anchored framework for measuring multi-tracer mass bias within matched cosmic voids. A sample of 102 matched void pairs is constructed to directly compare galaxy, subhalo, and dark matter mass distributions within an observationally constrained realisation of the local Universe. We find that both the galaxy-to-dark matter and subhalo-to-dark matter mass ratios decrease toward void centres, indicating that luminous and halo tracers become increasingly depleted relative to the underlying matter distribution in the deepest underdensities. In contrast, the galaxy-to-subhalo mass ratio exhibits substantially larger statistical uncertainties within the inner void regions ($r/R_{\rm v}\lesssim0.5$). By comparing measurements obtained using independent and common coordinate frameworks, we show that coordinate offsets contribute to the observed scatter but cannot fully account for the large uncertainties. The remaining uncertainty primarily arises from the severe scarcity of massive subhaloes ($\log_{10}(M_{\rm sub}/h^{-1}M_\odot)\ge11.8$) within void interiors, which greatly reduces the number of statistically valid measurements near void centres. Our results provide an empirical characterization of multi-tracer mass bias in observationally constrained cosmic environments and demonstrate the importance of accounting for coordinate consistency and tracer scarcity when interpreting such measurements in extreme underdense regions.
Comments13 pages, 6 figures, accepted for publication in MNRAS
