Constraining H0 in General Dark Energy Models from Sunyaev-Zeldovich/X-ray Technique and Complementary Probes

TL;DR

This study constrains the Hubble constant using Sunyaev-Zel'dovich/X-ray galaxy cluster data combined with BAO and CMB data, providing results consistent with previous measurements and exploring effects of curvature and dark energy equation of state.

Contribution

It introduces a joint analysis method combining SZE/X-ray, BAO, and CMB data to constrain H0 in general dark energy models, including nonflat and flat universes with constant w.

Findings

H0 in nonflat LCDM: 73.2^{+4.3}_{-3.7} km/s/Mpc

H0 in flat XCDM: 71.4^{+4.4}_{-3.4} km/s/Mpc

Results agree with independent measurements and show weak dependence on geometry.

Abstract

In accelerating dark energy models, the estimates of H0 from Sunyaev-Zel'dovich effect (SZE) and X-ray surface brightness of galaxy clusters may depend on the matter content (Omega_M), the curvature (Omega_K) and the equation of state parameter (w). In this article, by using a sample of 25 angular diameter distances from galaxy clusters obtained through SZE/X-ray technique, we constrain H_0 in the framework of a general LCDM models (free curvature) and a flat XCDM model with equation of state parameter, w=p_x/\rho_x (w=constant). In order to broke the degeneracy on the cosmological parameters, we apply a joint analysis involving the baryon acoustic oscillations (BAO) and the CMB Shift Parameter signature. By neglecting systematic uncertainties, for nonflat LCDM cosmologies we obtain $H_0=73.2^{+4.3}_{-3.7}$ km s$^{-1}$ Mpc$^{-1}$ (1sigma) whereas for a flat universe with constant equation of state parameter we find $H_0=71.4^{+4.4}_{-3.4}$ km s$^{-1}$ Mpc$^{-1}$ (1$\sigma$). Such results are also in good agreement with independent studies from the Hubble Space Telescope key project and recent estimates based on Wilkinson Microwave Anisotropy Probe, thereby suggesting that the combination of these three independent phenomena provides an interesting method to constrain the Hubble constant. In particular, comparing these results with a recent determination for a flat LCDM model using only the SZE technique and BAO [Cunha et al. MNRAS 379, L1 2007], we see that the geometry has a very weak influence on H0 estimates for this combination of data.