The Concordance of Weak Lensing and Escape Velocity Mass Estimates for Galaxy Clusters

TL;DR

This study finds strong agreement between weak lensing and escape velocity methods for measuring galaxy cluster masses, reducing previous discrepancies and supporting their combined use in cosmological research.

Contribution

The paper provides a revised comparison showing excellent agreement between weak lensing and escape velocity mass estimates for galaxy clusters, resolving prior inconsistencies.

Findings

Correlation between mass estimates is 0.679.

Mean relative difference is 0.02 dex, consistent with zero.

Observed scatter matches individual mass errors.

Abstract

In the $\Lambda$CDM paradigm, the masses of the galaxy clusters inferred using background galaxies via weak-lensing shear should agree with the masses measured using the galaxy projected radius-velocity phase-space data via the escape velocity profile. However, prior work indicates that the correlation between caustic-inferred escape masses and weak lensing masses is statistically consistent with zero. Based on recent advancements in the measurement of the escape edge and its physical interpretation, we conduct a revised comparison between these two independent mass inference techniques for 46 galaxy clusters between $0.05 \le z \le 0.3$ and over an order of magnitude in mass, $14.4 \le {\rm log}_{10} M/M_{\odot} \le 15.4$. We find excellent agreement, with a correlation ($0.679^{+0.046}_{-0.049}$), and a mean relative difference between the two mass measurements consistent with zero (0.02 $\pm$ 0.02 dex). The observed scatter between these direct mass estimates is 0.17 dex and is consistent with the reported individual mass errors, suggesting that there is no need for an additional intrinsic component. We discuss the important practical consequences of these results, focusing on the systematic uncertainties inherent to each technique, and their implications for cosmology.