发表机构
Inter University Centre for Astronomy and Astrophysics; Institute of Physics, University of Szczecin; Leiden Observatory, Leiden University; Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo（大学天文学与天体物理中心; 什切青大学物理研究所; 莱顿大学莱顿天文台; 东京大学宇宙物理与数学科学 Kavli 研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用相对聚类方法测量eRASS1 X射线星系团高低温子样本的大尺度偏置差，结合DES Y3弱透镜质量检验，在1σ内未发现显著组装偏置，但结果与FLAMINGO模拟预期一致，验证了该方法对未来巡天的适用性。
AI 中文摘要
晕组装偏置描述了晕聚类对晕质量以外性质的依赖性，为将晕组装历史与大尺度物质分布联系起来提供了一种手段。我们开发并测试了一种相对聚类方法，利用两个晕种群的星系对计数之比来测量它们大尺度偏置的差异。在线性区间内，该比值可与晕偏置之差相关联，而星系自相关函数则独立约束星系偏置。我们将该方法应用于来自eROSITA eRASS1星表的体积限X射线选择星系团，将其分为高、低温子样本，并在X射线光度、红移和曝光方面匹配分布。我们首先验证了线性近似的有效性，发现在4–10 h⁻¹Mpc范围内ξ(r)≪1.0。联合聚类分析得到b_g=1.610^{+0.018}_{-0.019}，偏置差Δb=0.8±1.1。DES Y3弱引力透镜测量为晕质量提供了独立检验，分别得到高、低温样本的log(M_{200m}/h⁻¹M_⊙)=14.33^{+0.07}_{-0.07}和14.33^{+0.10}_{-0.09}，质量差为Δlog M_{200m}=-0.01±0.12。因此，我们在1σ水平上未发现组装偏置的统计显著证据，但我们的测量结果与FLAMINGO模拟中类似晕种群测得的偏置差一致。因此，该结果并未排除模拟所预期的组装偏置水平，同时表明相对聚类方法为未来利用更大X射线星系团和星系巡天进行组装偏置测量提供了框架。
英文摘要
Halo assembly bias describes the dependence of halo clustering on properties beyond halo mass and provides a means of connecting halo assembly history to the large-scale matter distribution. We develop and test a relative clustering methodology for measuring differences in the large-scale bias of two halo populations using the ratio of their cluster--galaxy pair counts. In the linear regime, this ratio can be related to the difference in cluster bias, while the galaxy autocorrelation independently constrains the galaxy bias. We apply the method to a volume-limited X-ray selected galaxy clusters from the eROSITA eRASS1 catalogue, dividing them into high- and low-temperature subsamples with matched distributions in X-ray luminosity, redshift, and exposure. We first verify the validity of the linear approximation, finding $ξ(r)\ll1.0$ over $4$--$10\,h^{-1}\mathrm{Mpc}$. The joint clustering analysis yields $b_{\rm g}=1.610^{+0.018}_{-0.019}$ and a bias difference $Δb=0.8\pm1.1$. DES Y3 weak gravitational lensing measurements provide an independent test of the halo masses, yielding $\log(M_{200\mathrm{m}}/h^{-1}M_\odot)=14.33^{+0.07}_{-0.07}$ and $14.33^{+0.10}_{-0.09}$ for the high- and low-temperature samples, respectively, with a mass difference of $Δ\log M_{200\mathrm{m}}=-0.01\pm0.12$. We therefore find no statistically significant evidence for assembly bias at the $1σ$ level, but our measurement is consistent with the bias difference measured for analogous halo populations in the FLAMINGO simulation. The result therefore does not rule out assembly bias at the level expected from the simulation, while demonstrating that the relative clustering methodology provides a framework for future assembly-bias measurements with larger X-ray cluster and galaxy surveys.
Comments17 pages, 7 figures
