Cluster mass profile reconstruction with size and flux magnification on the HST STAGES survey

TL;DR

This paper demonstrates the first use of size and flux magnification in weak lensing to estimate individual cluster masses, successfully detecting known groups in the A901/902 supercluster with high significance.

Contribution

It introduces a Bayesian magnification method for cluster mass estimation and compares its effectiveness to traditional shear analysis in a real survey.

Findings

Magnification-only analysis detects supercluster groups with high significance.

Magnification constraints are consistent with shear constraints on cluster parameters.

Magnification yields slightly lower mass estimates compared to shear measurements.

Abstract

We present the first measurement of individual cluster mass estimates using weak lensing size and flux magnification. Using data from the HST-STAGES survey of the A901/902 supercluster we detect the four known groups in the supercluster at high significance using magnification alone. We discuss the application of a fully Bayesian inference analysis, and investigate a broad range of potential systematics in the application of the method. We compare our results to a previous weak lensing shear analysis of the same field finding the recovered signal-to-noise of our magnification-only analysis to range from 45% to 110% of the signal-to-noise in the shear-only analysis. On a case-by-case basis we find consistent magnification and shear constraints on cluster virial radius, and finding that for the full sample, magnification constraints to be a factor $0.77 \pm 0.18$ lower than the shear measurements.