Escape Velocity Mass of A1063

Abstract

We measure the radius–velocity phase-space edge profile of A1063 using galaxy redshifts from Karman et al. and Mercurio et al. 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 Navarro–Frenk–White profile, we find log _10 ( M _200,crit ) = ${15.40}_{-0.12}^{+0.06}$ M _⊙ , consistent to within 1 σ 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 σ lower than estimates made using X-ray data, in addition to the Gómezet al. velocity dispersion estimate. We measure the 1D velocity dispersion within r _200 to be ${\sigma }_{v}\,=\,{1477}_{-99}^{+87}$ km s ^−1 , which combined with our escape velocity mass, brings the dispersion for A1063 in-line with hydrodynamic cosmological simulations for the first time.

Keywords

• Cosmology
• Galaxy clusters
• Gravitational lensing
• Dark energy