Cluster Mass Profiles from a Bayesian Analysis of Weak Lensing Distortion and Magnification Measurements: Applications to Subaru Data

TL;DR

This paper presents a Bayesian method to derive model-independent galaxy cluster mass profiles from combined weak-lensing distortion and magnification data, applied to Subaru observations of five massive clusters, improving mass profile accuracy.

Contribution

The paper introduces a novel Bayesian approach that combines distortion and magnification measurements for model-independent mass profiling of galaxy clusters, extending to large radii.

Findings

Consistent distortion and magnification signals for all clusters.

Detection of stacked cluster profile at 37σ out to 1.7 times the virial radius.

Profiles well described by a generalized NFW profile, with some variations.

Abstract

We directly construct model-independent mass profiles of galaxy clusters from combined weak-lensing distortion and magnification measurements within a Bayesian statistical framework,which allows for a full parameter-space extraction of the underlying signal. This method applies to the full range of radius outside the Einstein radius, and recovers the absolute mass normalization. We apply our method to deep Subaru imaging of five high-mass (>10^{15}M_{sun}) clusters, A1689, A1703, A370, Cl0024+17, and RXJ1347-11, to obtain accurate profiles to beyond the virial radius (r_{vir}). For each cluster the lens distortion and magnification data are shown to be consistent with each other, and the total signal-to-noise ratio of the combined measurements ranges from 13 to 24 per cluster. We form a model-independent mass profile from stacking the clusters, which is detected at 37{\sigma} out to R ~ 1.7r_{vir}. The projected logarithmic slope steepens from -1.01 \pm 0.09 at R ~ 0.1r_{vir} to -1.92 \pm 0.51 at R ~ 0.9r_{vir}. We also derive for each cluster inner strong-lensing based mass profiles from deep HST/ACS observations, which we show overlap well with the outer Subaru-based profiles and together are well described by a generalized form of the Navarro-Frenk-White profile, except for the ongoing merger RXJ1347-11, with modest variations in the central cusp slope (-dln{\rho}/dlnr < 0.9). The improvement here from adding the magnification measurements is significant, ~30% in terms of cluster mass profile measurements, compared with the lensing distortion signal.