1204.1577 (Yookyung Noh et al.)

Disentangling correlated scatter in cluster mass measurements    [PDF]

Yookyung Noh, J. D. Cohn

The challenge of obtaining galaxy cluster masses is increasingly being addressed by multiwavelength measurements. As scatters in measured cluster masses are often sourced by properties of or around the clusters themselves, correlations between mass scatters are frequent and can be significant, with consequences for errors on mass estimates both directly and those obtained via stacking. Using a high resolution 250 Mpc/h side N-body simulation, combined with proxies for observational cluster mass measurements, we obtain mass scatter correlations and covariances for 243 individual clusters along ~96 lines of sight each, both separately and together. We use principal component analysis (PCA) to characterize scatter trends and variations between clusters. The dominant mass scatter combination identified by PCA is common to many clusters, and tends to dominate the mass scatters when viewing the cluster along its long axis. We also correlate cluster mass scatter, environmental and intrinsic properties, and use PCA to find shared trends between these. Our analysis is based upon estimated mass distributions for fixed true mass. Extensions to observational data would require further calibration from numerical simulations, tuned to specific observational survey selection functions and systematics.

View original: http://arxiv.org/abs/1204.1577