发表机构
Academia Sinica Institute of Astronomy and Astrophysics (ASIAA); Department of Astronomy, Yonsei University; Aix Marseille Univ, CNRS, CNES, LAM, Marseille, France; Department of Physics, University of California, Davis（中央研究院天文及天文物理研究所; 延世大学天文学系; 艾克斯-马赛大学、法国国家科学研究中心、法国国家空间研究中心、拉格朗日实验室; 加州大学戴维斯分校物理系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究用Jackknife方法检验强透镜模型中星系团晕与BCG偏移的必要性，发现MrMARTIAN框架下偏移不提升预测精度，质量分解非唯一，限制物理解释。
AI 中文摘要
由强透镜（SL）模型推断出的星系团尺度暗物质晕与最亮星系团星系（BCGs）之间的偏移已被用于研究星系团动力学和暗物质物理。然而，有必要检验这些偏移是否由SL数据本身所要求。我们研究了允许这些偏移是否提高预测精度，并考察了它们对放大率、时间延迟预测以及临界曲线位置的影响。我们使用Jackknife方法评估了Abell 370、RX J1347.5-1145和MACS J0416.1-2403的透镜模型，该方法评估对未纳入透镜重建的源系统的预测。模型使用MrMARTIAN构建，该工具将解析质量剖面与表示剖面未捕获的质量结构的正则化网格相结合。我们比较了在不同正则化权重下的固定和自由晕位置模型。对所有排除系统取平均的均方根值在自举不确定度内一致，而中位配对差值在三个星系团及所测试的正则化权重下均接近零。这些结果表明固定模型和自由模型具有相当的预测精度。总质量分布大体相似，尽管拟合的晕偏移幅度随正则化变化，表明质量分解并非唯一。对于这三个星系团，在MrMARTIAN框架内，SL数据并不要求透镜模型中BCG与星系团尺度晕之间存在偏移以提高预测精度。正则化网格与星系团尺度晕之间的质量分解并非唯一确定。这些发现限制了仅基于拟合晕位置的物理解释。放大率和时间延迟估计的模型依赖性也可能影响高红移源或哈勃常数的推断固有性质。
英文摘要
Offsets between cluster-scale dark matter halos and brightest cluster galaxies (BCGs) inferred from strong lensing (SL) models have been used to investigate cluster dynamics and dark matter physics. However, it is necessary to test whether these offsets are required by SL data themselves. We investigate whether allowing these offsets improves predictive accuracy and examine the effects on magnification, time-delay predictions, and critical curve positions. We evaluate lens models of Abell 370, RX J1347.5-1145, and MACS J0416.1-2403 using the jackknife method, which assesses predictions for source systems excluded from the lens reconstruction. Models are constructed with MrMARTIAN, which combines analytic mass profiles with a regularized grid that represents mass structure not captured by the profiles. We compare fixed and free halo position models across regularization weights. The root mean square values averaged over excluded systems agree within bootstrap uncertainties, while the median paired differences remain close to zero across all three clusters and tested regularization weights. These results indicate comparable predictive accuracy between the fixed and free models. The total mass distributions remain broadly similar, although the magnitudes of fitted halo offsets vary with regularization, showing that the mass decomposition is not unique. For these three clusters, offsets between BCGs and cluster-scale halos in the lens models are not required by the SL data to improve predictive accuracy within the MrMARTIAN framework. The mass decomposition between the regularized grid and cluster-scale halos is not uniquely determined. These findings limit physical interpretations based on fitted halo positions alone. The model dependence of magnification and time-delay estimation can also affect the inferred intrinsic properties of high-redshift sources or the Hubble constant.
Comments10 pages, 6 figures, submitted to A&A
