A new framework for understanding systematic errors in cluster lens modelling – I. Selection and treatment of cluster member galaxies
A new framework for understanding systematic errors in cluster lens modelling – I. Selection and treatment of cluster member galaxies
复制标题
理解星团透镜建模中系统误差的新框架—I.星团成员星系的选择和处理
DOI：
10.1093/mnras/stab2857
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发表时间：
2021
影响因子：
4.8
通讯作者：
Zimmerman, Dhruv T
中科院分区：
文献类型：
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作者：
Raney, Catie A;Keeton, Charles R;Zimmerman, Dhruv T
有了来自哈勃前沿场等项目的高质量数据，星系团透镜效应已经达到了这样的地步：模型是由系统的不确定性而不是统计的不确定性主导的。我们引入贝叶斯框架，通过确定不同的镜头建模选择如何影响结果来量化系统效应。我们的框架包括一个新的双样本测试，用于量化后验概率分布之间的差异，这些后验概率分布是通过蒙特卡洛马尔可夫链等方法采样的。我们使用这个框架来检查两个前沿场星系团（Abell 2744和MACS J0416.1-2403）中星系团成员星系的选择和处理。在选择成员星系时，深度和面积的选择会影响模型；我们发现，尽管径向极限可能取决于透镜图像的空间范围，但对于反波段星等极限（mm≥22.5等）和径向切割（mm≥90弧秒），模型结果是稳健的。质量通常是通过光度/质量比例关系分配给星系的。我们发现缩放关系的斜率对透镜模型参数有显著影响，但对透镜放大倍率的影响不大。有趣的是，尺度关系中的散点对两个场的影响是不同的。这一分析说明了我们的框架如何用于分析透镜建模选择，并指导未来的集群透镜方案。
With high-quality data from programs like theHubbleFrontier Fields, cluster lensing has reached the point that models are dominated by systematic rather than statistical uncertainties. We introduce a Bayesian framework to quantify systematic effects by determining how different lens modelling choices affect the results. Our framework includes a new two-sample test for quantifying the difference between posterior probability distributions that are sampled by methods like Monte Carlo Markov chains. We use the framework to examine choices related to the selection and treatment of cluster member galaxies in two of the Frontier Field clusters: Abell 2744 and MACS J0416.1–2403. When selecting member galaxies, choices about depth and area affect the models; we find that model results are robust for anI-band magnitude limit ofmlim≥ 22.5 mag and a radial cut ofrlim≥ 90 arcsec (from the centre of the field), although the radial limit likely depends on the spatial extent of lensed images. Mass is typically assigned to galaxies using luminosity/mass scaling relations. We find that the slopes of the scaling relations can have significant effects on lens model parameters but only modest effects on lensing magnifications. Interestingly, scatter in the scaling relations affects the two fields differently. This analysis illustrates how our framework can be used to analyse lens modelling choices and guide future cluster lensing programs.