Escape Velocity Mass of Abell S1063

TL;DR

This paper measures the escape velocity profile of galaxy cluster Abell S1063 to constrain its mass distribution, finding results consistent with lensing masses and aligning velocity dispersion with cosmological simulations.

Contribution

It introduces a method combining galaxy redshift data and cosmological modeling to directly infer the gravitational potential and mass of Abell S1063, with results consistent with lensing measurements.

Findings

Escape velocity profile constrains cluster mass.

Mass estimates agree with lensing within 1σ.

Velocity dispersion aligns with cosmological simulations.

Abstract

We measure the radius-velocity phase-space edge profile for Abell S1063 using galaxy redshifts from arXiv:1409.3507 and arXiv:2109.03305. Combined with a cosmological model and after accounting for interlopers and sampling effects, we infer the escape velocity profile. Using the Poisson equation, we then directly constrain the gravitational potential profile and find excellent agreement between three different density models. For the NFW profile, we find log$_{10}$(M$_{200},{\rm crit}$)= $15.40^{+0.06}_{-0.12}$M$_{\odot}$, consistent to within $1\sigma$ of six recently published lensing masses. We argue that this consistency is due to the fact that the escape technique shares no common systematics with lensing other than radial binning. These masses are 2-4$\sigma$ lower than estimates using X-ray data, in addition to earlier velocity dispersion estimates. We measure the 1D velocity dispersion within r$_{200}$ to be $\sigma_{v} = 1477^{+87}_{-99}$ km/s, which combined with our escape velocity mass, brings the dispersion for AS1063 in-line with hydrodynamic cosmological simulations for the first time.