AI 中文总结
该研究利用模拟，以普通方向平均次级偏差为基线，探讨暗物质晕的各向异性次级偏差，比较其与晕 - 环境对齐等环境表现的关系，明确了相关聚类信号及对晕定义的敏感性。
AI 中文摘要
次级偏差是晕聚类对晕质量以外属性的依赖性。利用z = 0的TNG300 - 1 - Dark模拟，研究各向异性次级偏差（ASB），即次级偏差随相对于晕主轴方向的变化。首先用普通的、方向平均的次级偏差（OSB）作为基线，比较三种环境表现：晕 - 环境对齐、外部物质各向异性和潮汐各向异性。匹配潮汐各向异性会抑制大部分OSB，而匹配晕 - 环境对齐或外部物质各向异性则不会。ASB表现不同，对形成时间、浓度和三轴性较弱，对自旋定义和短轴与长轴比则较强。匹配晕 - 环境对齐会大幅降低与自旋和形状相关的ASB信号，而匹配潮汐各向异性或外部物质轴比则基本保持不变。晕的定义对ASB影响小，但对低质量自旋偏差影响大。这些结果阐明了哪些聚类信号与晕 - 环境对齐、物质各向异性或潮汐各向异性相关，以及哪些对晕的定义敏感。
英文摘要
Secondary bias is the dependence of halo clustering on properties beyond halo mass. Using the $z=0$ TNG300-1-Dark simulation, we study anisotropic secondary bias (ASB): the variation of secondary bias with direction relative to the halo major axis. We first use ordinary, orientation-averaged secondary bias (OSB) as a baseline to compare three environmental manifestations: halo-environment alignment, outer matter anisotropy, and tidal anisotropy. Matching tidal anisotropy suppresses much of the OSB, whereas matching halo-environment alignment or outer matter anisotropy does not. ASB behaves differently. It is weak for formation time, concentration, and triaxiality, but strong for both spin definitions and minor-to-major axis ratio; slowly rotating and more elongated haloes are more strongly aligned with filamentary structure. Matching halo-environment alignment substantially reduces the spin- and shape-dependent ASB signals, whereas matching tidal anisotropy or the outer matter axis ratio leaves them largely intact. Halo definition has little impact on ASB, yet strongly affects low-mass spin bias: including unbound particles can move dense-environment haloes with low bound-particle spin into the high all-particle-spin sample. These results clarify which clustering signals are associated with halo-environment alignment, matter anisotropy, or tidal anisotropy, and which are sensitive to halo definition.
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