Testing cosmic acceleration for w(z) parametrizations using f_gas measurements in galaxy clusters

Abstract

In this paper, we study the cosmic acceleration for five dynamical dark energy models whose equation of state varies with redshift. The cosmological parameters of these models are constrained by performing a Markov chain Monte Carlo (MCMC) analysis using mainly gas mass fraction, f_gas, measurements in two samples of galaxy clusters: one reported by Allen et al., which consists of 42 points spanning the redshift range 0.05 < z < 1.1, and the other by Hasselfield et al. from the Atacama Cosmology Telescope survey, which consists of 91 data points in the redshift range 0.118 < {{z}} < 1.36. In addition, we perform a joint analysis with the measurements of the Hubble parameter H(z), baryon acoustic oscillations and the cosmic microwave background radiation from Wilkinson Microwave Anisotropy Probe (WMAP, Hinshaw et al.) and Planck measurements (Planck collaboration XIII) to estimate the equation-of-state parameters. We obtain that both f_gas samples provide consistent constraints on the cosmological parameters. We find that the f_gas data are consistent at the 2σ confidence level with a cosmic slowing down of the acceleration at late times for most of the parametrizations. The constraints of the joint analysis using WMAP and Planck measurements show that this trend disappears. We have confirmed that the f_gas probe provides competitive constraints on the dark energy parameters when a w(z) is assumed.