The Lack of Non-Thermal Motions in Galaxy Cluster Cores
  We report the non-thermal pressure fraction (Pnt/Ptot) obtained from a
three-dimensional triaxial analysis of 16 galaxy clusters in the CLASH sample
using gravitational lensing (GL) data primarily from Subaru and HST, X-ray
spectroscopic imaging from Chandra, and Sunyaev-Zel'dovich effect (SZE) data
from Planck and Bolocam. Our results span the approximate radial range
0.015-0.4R200m (35-1000 kpc). At cluster-centric radii smaller than 0.1R200m
the ensemble average Pnt/Ptot is consistent with zero with an upper limit of
nine per cent, indicating that heating from active galactic nuclei and other
relevant processes does not produce significant deviations from hydrostatic
equilibrium (HSE). The ensemble average Pnt/Ptot increases outside of this
radius to approximately 20 per cent at 0.4R200m, as expected from simulations,
due to newly accreted material thermalizing via a series of shocks. Also in
agreement with simulations, we find significant cluster-to-cluster variation in
Pnt/Ptot and little difference in the ensemble average Pnt/Ptot based on
dynamical state. We conclude that on average, even for diverse samples,
HSE-derived masses in the very central regions of galaxy clusters require only
modest corrections due to non-thermal motions.
