Chandra sample of nearby relaxed galaxy clusters:: Mass, gas fraction, and mass-temperature relation

We present gas and total mass profiles for 13 low-redshift, relaxed clusters spanning a temperature range 0.7 - 9 keV, derived from all available Chandra data of sufficient quality. In all clusters, gas-temperature profiles are measured to large radii (Vikhlinin et al.) so that direct hydrostatic mass estimates are possible to nearly r(500) or beyond. The gas density was accurately traced to larger radii; its profile is not described well by a beta model, showing continuous steepening with radius. The derived rho(tot) profiles and their scaling with mass generally follow the Navarro-Frenk-White model with concentration expected for dark matter halos in Lambda CDM cosmology. However, in three cool clusters, we detect a central mass component in excess of the Navarro-Frenk-White profile, apparently associated with their cD galaxies. In the inner region (r < 0.1r(500)), the gas density and temperature profiles exhibit significant scatter and trends with mass, but they become nearly self-similar at larger radii. Correspondingly, we find that the slope of the mass-temperature relation for these relaxed clusters is in good agreement with the simple self-similar behavior, M-500 proportional to T-alpha, where alpha = (1.5 - 1.6) +/- 0.1, if the gas temperatures are measured excluding the central cool cores. The normalization of this M - T relation is significantly, by approximate to 30%, higher than most previous X-ray determinations. We derive accurate gas mass fraction profiles, which show an increase with both radius and cluster mass. The enclosed f(gas) profiles within r(2500) similar or equal to 0.4r(500) have not yet reached any asymptotic value and are still far (by a factor of 1.5 - 2) from the universal baryon fraction according to the cosmic microwave background (CMB) observations. The f(gas) trends become weaker and its values closer to universal at larger radii, in particular, in spherical shells r(2500) < r < r(500).