发表机构
University of California, Santa Cruz; Santa Cruz Institute for Particle Physics; The Ohio State University; University of Pennsylvania; Southern Methodist University; Stanford University; SLAC National Accelerator Laboratory; Lawrence Berkeley National Laboratory; Université Paris Cité; CNRS(/IN2P3)（加州大学圣克鲁兹分校; 圣克鲁兹粒子物理研究所; 俄亥俄州立大学; 宾夕法尼亚大学; 南方卫理公会大学; 斯坦福大学; SLAC国家加速器实验室; 劳伦斯伯克利国家实验室; 巴黎西岱大学; 法国国家科学研究中心）
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Cardinal模拟和DES Y3数据，发现redMaPPer选择星系团中35%的速度弥散异常值主要由视线方向投影结构造成，尤其在低 richness 和高红移处，影响质量估计。
AI 中文摘要
星系团丰度的演化是宇宙学的有力探针，但其有效性取决于我们理解和控制星系团选择及质量估计中系统误差的能力。我们研究了Cardinal模拟中redMaPPer选择的星系团，该模拟再现了DES Y3的观测条件。具体而言，我们调查了12,272个模拟星系团中成员星系沿视线方向的速度分布。我们发现，相当大比例的星系团（35%）的速度弥散相对于其 richness（ richness）偏高，异常值群体与主群体之间的偏移约为400 km/s。在DES Y3数据中也发现了类似的速度弥散异常值群体。在低 richness 子样本中，几乎所有异常值（98%）具有非高斯速度分布，并且它们比主群体更可能具有显著的速度子结构。这些星系团也倾向于比具有典型速度弥散的星系团具有更高的红移，并且它们在暗物质晕质量与 richness 之间表现出更大的散射。总体而言，我们的结果表明，redMaPPer选择的样本受到视线方向结构的显著污染，特别是在高红移和低 richness 的情况下。与Buzzard模拟的比较显示了类似的结果。
英文摘要
The evolution of galaxy cluster abundance is a powerful probe of cosmology, but its efficacy depends on our ability to understand and control for systematics in the selection and mass estimation of clusters. We study redMaPPer-selected clusters in the Cardinal simulation, which simulates the DES Y3 observational conditions. Specifically, we investigate the line-of-sight velocity distributions of cluster member galaxies in 12,272 simulated clusters. We find that a significant fraction of clusters, 35%, have velocity dispersions that are high compared to their richness with an offset of $\sim 400$ km s$^{-1}$ between the outliers and the main population. A similar population of velocity dispersion outliers was found in the DES Y3 data. Nearly all of the outliers (98%) in a low-richness subsample have non-Gaussian velocity distributions, and they are more likely than the main population to have significant velocity substructure. These clusters also tend to have higher redshifts than clusters with typical velocity dispersions, and they show a larger scatter between halo mass and richness. Overall, our results point to a significant contamination of redMaPPer-selected samples from line of sight structure, particularly at high redshifts and low richness. Comparison to the Buzzard simulations shows similar results.
Comments31 pages, submitted to ApJ
