Testing redMaPPer centring probabilities using galaxy clustering and galaxy–galaxy lensing
Testing redMaPPer centring probabilities using galaxy clustering and galaxy–galaxy lensing
复制标题
使用星系聚类和星系-星系透镜测试 redMapPer 中心概率
DOI：
10.1093/mnras/sty2013
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发表时间：
2017
影响因子：
4.8
通讯作者：
E. Rykoff
中科院分区：
文献类型：
--
作者：
C. Hikage;R. Mandelbaum;A. Leauthaud;E. Rozo;E. Rykoff
星系团定心是利用星系调查进行精确宇宙学研究的一个关键问题。对中心星系的错误识别导致了各种研究的系统化，如星团透镜、卫星运动学和星系群集。红色序列匹配过滤概率渗透（redMaPPer）根据光度信息估计每个成员星系位于中心的概率，而不是指定一个中心星系。redMaPPer的估计可以用来校准偏离中心的效果，然而，中心算法之前还没有经过很好的测试。我们使用redMaPPer星系团与光度测量的红星系和星系-星系透镜之间的投影相互关系来测试redMaPPer星系团目录的中心概率。我们重点研究了redMaPPer星系团的子样本，其中redMaPPer中心星系（rmcg）不是最亮的成员星系（BMEM），它们都有光谱红移。这个子样本占整个集群样本的近10%。我们发现rmcg和BMEMs之间的相互关系测量有明显的差异，在高斯偏移模型中，rmcg的中心概率为74$\pm$10%， BMEMs的中心概率为13$\pm$4%，在NFW偏移模型中，rmcg的中心概率为78$\pm$9%， BMEMs的中心概率为5$\pm$5%。这些值与redMaPPer报告的居中概率值（RMCG为75%，BMEMs为10%）在1$\sigma$范围内一致。我们的分析提供了redMaPPer集中概率的强一致性测试。我们的结果表明，redMaPPer的集中概率是可靠的估计。我们确认星系团中最亮的星系并不总是中央星系，正如之前的研究所显示的那样。
Galaxy cluster centring is a key issue for precision cosmology studies using galaxy surveys. Mis-identification of central galaxies causes systematics in various studies such as cluster lensing, satellite kinematics, and galaxy clustering. The red-sequence Matched-filter Probabilistic Percolation (redMaPPer) estimates the probability that each member galaxy is central from photometric information rather than specifying one central galaxy. The redMaPPer estimates can be used for calibrating the off-centring effect, however, the centring algorithm has not previously been well-tested. We test the centring probabilities of redMaPPer cluster catalog using the projected cross correlation between redMaPPer clusters with photometric red galaxies and galaxy-galaxy lensing. We focus on the subsample of redMaPPer clusters in which the redMaPPer central galaxies (RMCGs) are not the brightest member galaxies (BMEM) and both of them have spectroscopic redshift. This subsample represents nearly 10% of the whole cluster sample. We find a clear difference in the cross-correlation measurements between RMCGs and BMEMs, and the estimated centring probability is 74$\pm$10% for RMCGs and 13$\pm$4% for BMEMs in the Gaussian offset model and 78$\pm$9% for RMCGs and 5$\pm$5% for BMEMs in the NFW offset model. These values are in agreement with the centring probability values reported by redMaPPer (75% for RMCG and 10% for BMEMs) within 1$\sigma$. Our analysis provides a strong consistency test of the redMaPPer centring probabilities. Our results suggest that redMaPPer centring probabilities are reliably estimated. We confirm that the brightest galaxy in the cluster is not always the central galaxy as has been shown in previous works.