Universal Profiles of the Intracluster Medium from Suzaku X-Ray and
  Subaru Weak Lensing Obesrvations
  We conduct a joint X-ray and weak-lensing study of four relaxed galaxy
clusters (Hydra A, A478, A1689 and A1835) observed by both Suzaku and Subaru
out to virial radii, with an aim to understand recently-discovered unexpected
feature of the ICM in cluster outskirts. We show that the average
hydrostatic-to-lensing total mass ratio for the four clusters decreases from
\sim 70% to \sim 40% as the overdensity contrast decreases from 500 to the
virial value.The average gas mass fraction from lensing total mass estimates
increases with cluster radius and agrees with the cosmic mean baryon fraction
within the virial radius, whereas the X-ray-based gas fraction considerably
exceeds the cosmic values due to underestimation of the hydrostatic mass. We
also develop a new advanced method for determining normalized cluster radial
profiles for multiple X-ray observables by simultaneously taking into account
both their radial dependence and multivariate scaling relations with
weak-lensing masses. Although the four clusters span a range of halo mass,
concentration, X-ray luminosity and redshift, we find that the gas entropy,
pressure, temperature and density profiles are all remarkably self-similar when
scaled with the lensing M_200 mass and r_200 radius.The entropy monotonically
increases out to \sim 0.5r_200 following the accretion shock heating model
K(r)\propto r^1.1, and flattens at \simgt 0.5r_200.The universality of the
scaled entropy profiles indicates that the thermalization mechanism over the
entire cluster region (>0.1r_200) is controlled by gravitation in a common to
all clusters, although the heating efficiency in the outskirts needs to be
modified from the standard law.The bivariate scaling functions of the gas
density and temperature reveal that the flattening of the outskirts entropy
profile is caused by the steepening of the temperature, rather than the
flattening of the gas density.
