arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2109.04092astro-ph.CO
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用DESI星系团和普朗克探测两两kSZ效应

Detection of pairwise kSZ effect with DESI galaxy clusters and Planck

Ziyang Chen, Pengjie Zhang, Xiaohu Yang, Yi Zheng

摘要:

我们报告的$5σ$检测成对运动的Sunyaev-Zel 'dovich(kSZ)效应,结合星系团在DESI成像调查和普朗克温度图。数据和分析方法的改进促进了检测。对于数据,我们采用了最近发布的星系群目录(Y20:\cite{yang2020extended})与$\sim 10^6$鲁棒识别的群体,并构建各种星系团样本的kSZ测量。Y20星表还提供了晕质量的估算,这进一步改进了$\sim 10\%$对kSZ的测量。对于分析方法,我们通过极大似然分析得到了两两kSZ的最优估计。它还自洽地处理潜在的系统误差。基线星系团样本,包含$1.2\times 10^5$最丰富的星系团的典型质量~ $ 10^{14} M_{\odot}/h$在典型的红移$0.2$ - $0.5$,排除了零假设在$5σ$。当与来自模拟的成对kSZ模板拟合时,在$4.7σ$处检测信号,并且平均光学深度被约束为$\barτ_e=(1.66\pm 0.35)\times 10^{-4}$。我们进行各种内部检查,不同的集群选择标准,不同的天空覆盖和红移范围,不同的CMB地图,不同的过滤器大小,不同的处理潜在的系统和协方差矩阵。在各种聚类样本中,使用$2.5\leq $ S/N $\leq 5.6$和可接受的$χ^2_{\rm min}$一致检测到kSZ效应。S/N受到普朗克分辨率和photo-z精度的限制,因此可以通过DESI光谱红移信息和其他CMB实验显着改善。

英文摘要:

We report a $5σ$ detection of the pairwise kinematic Sunyaev-Zel'dovich (kSZ) effect, combining galaxy clusters in DESI imaging surveys and the Planck temperature maps. The detection is facilitated by both improvements in the data and in the analysis method. For the data, we adopt the recently released galaxy group catalog (Y20: \cite{yang2020extended}) with $\sim 10^6$ robustly-identified groups, and construct various galaxy cluster samples for the kSZ measurement. The Y20 catalogue also provides estimation of halo mass, which further improves the kSZ measurement by $\sim 10\%$. For the analysis method, we derive an optimal estimator of pairwise kSZ through the maximum likelihood analysis. It also handles potential systematic errors self-consistently. The baseline cluster sample, containing the $1.2\times 10^5$ richest galaxy clusters of typical mass ~$ 10^{14} M_{\odot}/h$ at typical redshift $0.2$-$0.5$, rules out the null hypothesis at $5σ$. When fitting with a pairwise kSZ template from simulations, the signal is detected at $4.7σ$ and the average optical depth is constrained as $\barτ_e=(1.66\pm 0.35)\times 10^{-4}$. We perform various internal checks, with different cluster selection criteria, different sky coverage and redshift range, different CMB maps, different filter sizes, different treatments of potential systematics and the covariance matrix. The kSZ effect is consistently detected with $2.5\leq $S/N$\leq 5.6$ and acceptable $χ^2_{\rm min}$, across a variety of cluster samples. The S/N is limited by both the Planck resolution and the photo-z accuracy, and therefore can be significant improved with DESI spectroscopic redshift information and with other CMB experiments.

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