宿主星系团依赖性及视线效应对星系-星系强引力透镜的影响
Host Dependence and Line-of-Sight Effects on Galaxy-Galaxy Strong Lensing in Clusters
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中文总结 AI 辅助
本研究探讨星系团中GGSL观测与模拟的差异，发现视线相关物质、重子物理及爱因斯坦半径影响GGSL概率，视场定义会改变差异程度，尚未明确解决该差异问题。
中文摘要 AI 辅助
观测中发现的星系团内星系-星系强引力透镜（GGSL）事件的截面，多次被证实高于宇宙学模拟结果。本研究采用更新的模拟方法，重新探讨该差异，并研究GGSL概率$P_{\rm GGSL}$对宿主星系团引力透镜特性、重子物理、相关及非相关视线结构的依赖性。研究发现，沿视线方向距星系团约35共动百万秒差距（cMpc）内的相关物质，会使典型系统的$P_{\rm GGSL}$提升数个百分点，对最有效的透镜系统则提升约15%；在固定星系团质量的条件下，仅含暗物质的模拟得到的GGSL概率，比流体动力学模拟低达一个数量级。此外，$P_{\rm GGSL}$对宿主星系团的爱因斯坦半径有强烈依赖性，近似满足$P_{\rm GGSL} \boldsymbol{\theta}_{\rm E}^{2}$的标度关系。在质量和爱因斯坦半径两方面匹配模拟与观测的星系团，似乎能缩小与此前对比的差异，但本分析并未明确解决GGSL差异问题，因为推断的张力强烈依赖于视场定义：方形视场的结果与模拟大致一致，而以星系团成员为边界的视场则使观测概率高出约2-3倍。在观测与模拟采用匹配的选择函数和测量方法之前，残余张力无法明确归因于天体物理或宇宙学因素。
英文摘要
The cross section for galaxy-galaxy strong lensing (GGSL) events in galaxy clusters has repeatedly been found to be higher in observations than in cosmological simulations. We revisit this discrepancy using updated simulation methodology and investigate the dependence of the GGSL probability, $P_{\rm GGSL}$, on host-cluster lensing properties, baryonic physics, and correlated and uncorrelated line-of-sight structure. We find that correlated material within $\sim 35$ cMpc of the cluster along the line of sight enhances $P_{\rm GGSL}$ by a few percent for typical systems and by up to $\sim15\%$ for the most efficient lenses. At fixed cluster mass, dark-matter-only simulations yield GGSL probabilities up to an order of magnitude lower than hydrodynamical simulations. We also find a strong dependence on the host-cluster Einstein radius, with an approximate scaling $P_{\rm GGSL} \propto θ_{\rm E}^{2}$. Matching simulated and observed clusters in both mass and Einstein radius seems to reduce the discrepancy relative to previous comparisons. However, our analysis does not clearly resolve the GGSL discrepancy, as the inferred tension depends strongly on the field-of-view definition: square fields are approximately consistent with simulations, while cluster member-bounded fields yield observed probabilities a factor of $\sim 2-3$ higher. Until observations and simulations share a matched selection function and matched measurement methodology, the residual tension cannot be cleanly attributed to either astrophysics or cosmology.
发表机构
- Massachusetts Institute of Technology（麻省理工学院）
- Yale University（耶鲁大学）
- University of Michigan（密歇根大学）
- INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna（意大利国家天体物理研究所博洛尼亚天文与空间科学观测站）
- Philipps Universität Marburg（马尔堡菲利普斯大学）
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