Determination of the cosmic distance scale from Sunyaev-Zel'dovich effect and Chandra X-ray measurements of high-redshift galaxy clusters.
BONAMENTE M., JOY M.K., LAROQUE S.J., CARLSTROM J.E., REESE E.D. and DAWSON K.S.
Abstract (from CDS):
We determine the distance to 38 clusters of galaxies in the redshift range 0.14≤z≤0.89 using X-ray data from Chandra and Sunyaev-Zeldovich effect (SZE) data from the Owens Valley Radio Observatory and the Berkeley-Illinois-Maryland Association interferometric arrays. The cluster plasma and dark matter distributions are analyzed using a hydrostatic equilibrium model that accounts for radial variations in density, temperature, and abundance, and the statistical and systematic errors of this method are quantified. The analysis is performed via a Markov chain Monte Carlo technique that provides simultaneous estimation of all model parameters. We measure a Hubble constant of H0=76.9+3.9–3.4+10.0–8.0 km/s/Mpc (statistical followed by systematic uncertainty at 68% confidence) for an ΩM=0.3, ΩΛ=0.7 cosmology. We also analyze the data using an isothermal β-model that does not invoke the hydrostatic equilibrium assumption and find H0=73.7+4.6–3.8+9.5–7.6km/s/Mpc; to avoid effects from cool cores in clusters, we repeated this analysis excluding the central 100 kpc from the X-ray data and find H0=77.6+4.8–4.3+10.1–8.2 km/s/Mpc (statistical followed by systematic uncertainty at 68% confidence). The consistency between the models illustrates the relative insensitivity of SZE/X-ray determinations of H0 to the details of the cluster model. Our determination of the Hubble parameter in the distant universe agrees with the recent measurement from the Hubble Space Telescope Key Project that probes the nearby universe.