论文标题
热样本的超级样本协方差
Super-sample covariance of the thermal Sunyaev-Zel'dovich effect
论文作者
论文摘要
Thermal Sunyaev-Zel'dovich（TSZ）效应是宇宙学的强大探针。 TSZ功率谱测量中的统计误差以调查量中的大量群集的存在为主，这些集群易于以单个群集为基础。首先，我们研究了超级样品协方差（SSC）对TSZ功率谱测量的影响，并发现样品方差主要由调查量中大量群集的Poisson数量波动引起的连接的非高斯（CNG）协方差。其次，我们发现从分析中删除这种单独检测的大量群集会显着降低CNG贡献，从而使SSC成为样本方差的主要来源。然后，我们根据Fisher分析表明，从剩余的扩散TSZ效应中测得的功率谱可用于获得对宇宙学参数以及静水质量偏置参数的严格约束。我们的方法提供了单个TSZ群集计数的互补用途以及用于宇宙学和簇内气体物理学的弥漫性TSZ信号的功率谱测量。
The thermal Sunyaev-Zel'dovich (tSZ) effect is a powerful probe of cosmology. The statistical errors in the tSZ power spectrum measurements are dominated by the presence of massive clusters in a survey volume that are easy to identify on individual cluster basis. First, we study the impact of super sample covariance (SSC) on the tSZ power spectrum measurements, and find that the sample variance is dominated by the connected non-Gaussian (cNG) covariance arising mainly from Poisson number fluctuations of massive clusters in the survey volume. Second, we find that removing such individually-detected, massive clusters from the analysis significantly reduces the cNG contribution, thereby leading the SSC to be a leading source of the sample variance. We then show, based on Fisher analysis, that the power spectrum measured from the remaining diffuse tSZ effects can be used to obtain tight constraints on cosmological parameters as well as the hydrostatic mass bias parameter. Our method offers complementary use of individual tSZ cluster counts and the power spectrum measurements of diffuse tSZ signals for cosmology and intracluster gas physics.
