LoCuSS: A Comparison of Cluster Mass Measurements from XMM-Newton and
  Subaru - Testing Deviation from Hydrostatic Equilibrium and Non-Thermal
  Pressure Support
  We compare X-ray hydrostatic and weak-lensing mass estimates for a sample of
12 clusters that have been observed with both XMM-Newton and Subaru. At an
over-density of \Delta=500, we obtain 1-M^{X}/M^{WL}=0.01+/-0.07 for the whole
sample. We also divided the sample into undisturbed and disturbed sub-samples
based on quantitative X-ray morphologies using asymmetry and fluctuation
parameters, obtaining 1-M^{X}/M^{WL}=0.09+/-0.06 and -0.06+/-0.12 for the
undisturbed and disturbed clusters, respectively. In addition to non-thermal
pressure support, there may be a competing effect associated with adiabatic
compression and/or shock heating which leads to overestimate of X-ray
hydrostatic masses for disturbed clusters, for example, in the famous merging
cluster A1914. Despite the modest statistical significance of the mass
discrepancy, on average, in the undisturbed clusters, we detect a clear trend
of improving agreement between M^{X} and M^{WL} as a function of increasing
over-density, M^{X}/M^{WL}=(0.908+/-0.004)+(0.187+/-0.010) \log_{10}(\Delta
/500). We also examine the gas mass fractions, f_{gas}=M^{gas}/M^{WL}, finding
that they are an increasing function of cluster radius, with no dependence on
dynamical state, in agreement with predictions from numerical simulations.
Overall, our results demonstrate that XMM-Newton and Subaru are a powerful
combination for calibrating systematic uncertainties in cluster mass
measurements.
