New constraints on H ₀ and Ω _m from SZE/X-ray data and baryon acoustic oscillations

Abstract

The Hubble constant, H ₀, sets the scale of the size and age of the Universe and its determination from independent methods is still worthwhile to be investigated. In this article, by using the Sunyaev–Zeldovich effect and X-ray surface brightness data from 38 galaxy clusters observed by Bonamente et al. (Astrophys J 647:25, 2006), we obtain a new estimate of H ₀ in the context of a flat Λ CDM model. There is a degeneracy on the mass density parameter (Ω _m ) which is broken by applying a joint analysis involving the baryon acoustic oscillations (BAO) as given by Sloan Digital Sky Survey. This happens because the BAO signature does not depend on H ₀. Our basic finding is that a joint analysis involving these tests yield ${H_0 = 76.5^{+3.35}_{-3.33}}$ km/s/mpc and ${\Omega_{m} = 0.27^{+0.03}_{-0.02}}$. Since the hypothesis of spherical geometry assumed by Bonamente et al. is questionable, we have also compared the above results to a recent work where a sample of galaxy clusters described by an elliptical profile was used in analysis.