New constraints on H_0 and Omega_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-Zel`dovich effect and X-ray surface brightness data from 38 galaxy clusters observed by Bonamente {\it{et al.}} (2006), we obtain a new estimate of $H_0$ in the context of a flat $\Lambda$CDM model. There is a degeneracy on the mass density parameter (${\Omega }_m$) which is broken by applying a joint analysis involving the baryon acoustic oscillations (BAO) as given by Sloan Digital Sky Survey (SDSS). This happens because the BAO signature does not depend on $H_0$. Our basic finding is that a joint analysis involving these tests yield $H_0=0.765_{-0.033}^{+0.035}$ km s${}^{-1}$ Mpc${}^{-1}$ and ${\Omega }_m=0.27_{-0.02}^{+0.03}$. Since the hypothesis of spherical geometry assumed by Bonamente {\it {et al.}} is questionable, we have also compared the above results to a recent work where a sample of triaxial galaxy clusters has been considered.

8 pages, 4 figures, 1 table, accepted version in the general relativity and gravitation