arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1208.0605astro-ph.CO
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称重巨人队- III。精确计算星系团弱透镜质量的方法和测量

Weighing the Giants - III. Methods and Measurements of Accurate Galaxy Cluster Weak-Lensing Masses

Douglas E. Applegate, Anja von der Linden, Patrick L. Kelly, Mark T. Allen, Steven W. Allen, Patricia R. Burchat, David L. Burke, Harald Ebeling, Adam Mantz, R. Glenn Morris

摘要:

我们报告了51个已知的X射线最明亮的星系团的弱透镜质量。这个星系团样本,在本系列论文的前面介绍过,红移范围为0.15 < z_cl < 0.7,非常适合校准当前星系团宇宙学实验的质量代理。用标准的“色切”透镜法从每个视场的三个滤光片测光测量团簇质量。此外,对于27个具有至少五个滤光片测光的星系团,我们使用一种新方法测量高精度质量,该方法利用了单个星系的测光红移后验概率分布中的所有信息。使用模拟的基础上的COSMOS-30目录,我们证明了控制系统偏差的平均质量的样品与这种方法,从光度红移偏差和相关的不确定性,优于3%。相比之下,我们表明,使用单点估计的全部光度红移后验分布的地方可以导致显着的红移依赖的集群群众的偏见。我们的新的光度红移为基础的方法的性能,使我们能够校准“色切”质量的所有51个集群在本样本的总系统的不确定性约7%的平均质量,足以显着改善当前的宇宙学约束的水平,从星系团。我们的研究结果预示着未来的宇宙学研究的集群,可能减少需要详尽的光谱校准调查相比,其他技术,当深,多过滤器的光学和近红外成像调查加上强大的光度红移方法。

英文摘要:

We report weak-lensing masses for 51 of the most X-ray luminous galaxy clusters known. This cluster sample, introduced earlier in this series of papers, spans redshifts 0.15 < z_cl < 0.7, and is well suited to calibrate mass proxies for current cluster cosmology experiments. Cluster masses are measured with a standard `color-cut' lensing method from three-filter photometry of each field. Additionally, for 27 cluster fields with at least five-filter photometry, we measure high-accuracy masses using a new method that exploits all information available in the photometric redshift posterior probability distributions of individual galaxies. Using simulations based on the COSMOS-30 catalog, we demonstrate control of systematic biases in the mean mass of the sample with this method, from photometric redshift biases and associated uncertainties, to better than 3%. In contrast, we show that the use of single-point estimators in place of the full photometric redshift posterior distributions can lead to significant redshift-dependent biases on cluster masses. The performance of our new photometric redshift-based method allows us to calibrate `color-cut` masses for all 51 clusters in the present sample to a total systematic uncertainty of ~7% on the mean mass, a level sufficient to significantly improve current cosmology constraints from galaxy clusters. Our results bode well for future cosmological studies of clusters, potentially reducing the need for exhaustive spectroscopic calibration surveys as compared to other techniques, when deep, multi-filter optical and near-IR imaging surveys are coupled with robust photometric redshift methods.

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