The impact of projection effects on cluster observables: stacked lensing and projected clustering
The impact of projection effects on cluster observables: stacked lensing and projected clustering
复制标题
投影效应对集群可观测量的影响：堆叠透镜和投影集群
DOI：
10.1093/mnras/staa1646
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发表时间：
2020
影响因子：
4.8
通讯作者：
Osato Ken
中科院分区：
文献类型：
--
作者：
Sunayama Tomomi;Park Youngsoo;Takada Masahiro;Kobayashi Yosuke;Nishimichi Takahiro;Kurita Toshiki;More Surhud;Oguri Masamune;Osato Ken
光学星系团发现器不可避免地会受到投影效应的影响，在这种情况下，它会错误地将视线上多个光晕中的星系叠加为一个星系团。利用从宇宙N体模拟建立的模拟星系表，我们量化了这些投影效应的影响，特别关注星团宇宙学感兴趣的观测数据，即星团透镜和星团聚集信号。我们发现，由我们的星系团发现器算法识别的“观察到的”星系团呈现出与基于统计各向同性光晕模型的预期相偏离的透镜和聚集信号--虽然这两个信号在小尺度上与光晕模型的预期一致，但它们在大尺度上表现出意外的增强，分别高达1.2或1.4倍。我们将这些升压的来源确定为光学星系仪对嵌入在灯丝中的星团的固有选择偏差，这些星团与视线对齐，并表明整个样本中此类星团的少数()负责这种观察到的升压。我们讨论了我们的结果对以前的光学星系团研究的意义，以及在未来的星系团宇宙学分析中识别和减轻投影效应的前景。
An optical cluster finder inevitably suffers fromprojection effects, where it misidentifies a superposition of galaxies in multiple haloes along the line of sight as a single cluster. Using mock cluster catalogues built from cosmologicalN-body simulations, we quantify the impact of these projection effects with a particular focus on the observables of interest for cluster cosmology, namely the cluster-lensing and the cluster-clustering signals. We find that ‘observed’ clusters, i.e. clusters identified by our cluster finder algorithm, exhibit lensing and clustering signals that deviate from expectations based on a statistically isotropic halo model – while both signals agree with halo model expectations on small scales, they show unexpected boosts on large scales by up to a factor of 1.2 or 1.4, respectively. We identify the origin of these boosts as the inherent selection bias of optical cluster finders for clusters embedded within filaments aligned with the line of sight and show that a minority () of such clusters within the entire sample is responsible for this observed boost. We discuss the implications of our results on previous studies of optical cluster, as well as prospects for identifying and mitigating projection effects in future cluster cosmology analyses.