Cosmological implications of the dark matter equation of state

Abstract

In this paper, we study a model which is composed of the cosmological constant and dark matter with nonzero equation of state parameter, which could be called as [Formula: see text]wDM. In the synchronous gauge, we obtain the perturbation equations of dark matter, and deduce the evolution equations of growth factor about the dark matter and baryons. Based on the Markov Chain Monte Carlo (MCMC) method, we constrain this model by the recently available cosmic observations which include cosmic microwave background (CMB) radiation, baryon acoustic oscillation (BAO), type Ia supernovae (SNIa) and [Formula: see text] data points from redshift-space distortion (RSD). The results present a tighter constraint on the model than the case without [Formula: see text] data. In 3[Formula: see text] regions, we find the dark matter equation of state parameter [Formula: see text]. The currently available cosmic observations do not favor the nonzero dark matter equation of state parameter, no deviation from the lambda cold dark matter ([Formula: see text]CDM) model is found in 1[Formula: see text] region.