Resolving the hydrostatic mass profiles of galaxy clusters at z~1 with
  XMM-Newton and Chandra
  We present a detailed study of the integrated total hydrostatic mass profiles
of the five most massive ($M^{\mathrm{SZ}}_{500} > 5 \times 10^{14}$
M$_{\odot}$) galaxy clusters selected at $z\sim1$ via the Sunyaev-Zel'dovich
effect. These objects represent an ideal laboratory to test structure formation
models where the primary driver is gravity. Optimally exploiting
spatially-resolved spectroscopic information from XMM-Newton and Chandra
observations, we used both parametric (forward, backward) and non-parametric
methods to recover the mass profiles, finding that the results are extremely
robust when density and temperature measurements are both available. Our X-ray
masses at $R_{500}$ are higher than the weak lensing masses obtained from the
Hubble Space Telescope (HST), with a mean ratio of $1.39^{+0.47}_{-0.35}$. This
offset goes in the opposite direction to that expected in a scenario where the
hydrostatic method yields a biased, underestimated, mass. We investigated halo
shape parameters such as sparsity and concentration, and compared to local
X-ray selected clusters, finding hints for evolution in the central regions (or
for selection effects). The total baryonic content is in agreement with the
cosmic value at $R_{500}$. Comparison with numerical simulations shows that the
mass distribution and concentration are in line with expectations. These
results illustrate the power of X-ray observations to probe the statistical
properties of the gas and total mass profiles in this high-mass, high-redshift
regime.
