Combined constraints on modified Chaplygin gas model from cosmological observed data: Markov Chain Monte Carlo approach

Abstract

We use the Markov Chain Monte Carlo method to investigate a global constraints on the modified Chaplygin gas (MCG) model as the unification of dark matter and dark energy from the latest observational data: the Union2 dataset of type supernovae Ia (SNIa), the observational Hubble data (OHD), the cluster X-ray gas mass fraction, the baryon acoustic oscillation (BAO), and the cosmic microwave background (CMB) data. In a flat universe, the constraint results for MCG model are, b h 2 = 0.02263 +0.00184 −0.00162 (1σ ) +0.00213 −0.00195 (2σ ), B s = 0.7788 +0.0736 −0.0723 (1σ ) +0.0918 −0.0904 (2σ ), α = 0.1079 +0.3397 −0.2539 (1σ ) +0.4678 −0.2911 (2σ ), B = 0.00189 +0.00583 −0.00756 (1σ ) +0.00660 −0.00915 (2σ ), and H 0 = 70.711 +4.188 −3.142 (1σ ) +5.281 −4.149 (2σ ).Keywords Modified Chaplygin gas (MCG) · Unification of dark matter and dark energy

On the concordance of cosmological data in the case of the generalized Chaplygin gas

“…−0.25 [26] and the 1σ interval α ∈ [0.08, 0.31] [27], should be of the order of those expected in the generalised Chaplygin gas. Their CMB analysis also makes use of the shift parameter R.…”

“…As a modification of the generalised Chaplygin gas, the equation of state p = βρ − A/ρ α is proposed, but it is found in [26,27] that β has to be very small. Thus, both the energy density and the equation of state approach those of the generalised Chaplygin gas.…”

“…This generated again a large interest in the Chaplygin cosmologies and its variants, see e. g. [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Most papers assume a flat universe when the allowed parameter space is estimated according to various cosmological data.…”

Stability of effective thin-shell wormholes under Lorentz symmetry breaking supported by dark matter and dark energy

“…For this purpose, many kinds of energy of states (EOS) are used that are also familiar to us from cosmological models, such as Chaplygin gas [59], generalized Chaplygin gas [60], modified Chaplygin gas (MCG) [61], barotropic fluids [26], logarithmic gas, etc. [13,14,16,18,19,32,33,62]. The increasing number and precision of cosmological experiments has revealed more evidence of the standard ΛCDM model, which is an accurate description of gravity on cosmological scales [63][64][65][66][67][68].…”

Constraints on the dark matter sound speed from galactic scales: The cases of the modified and extended Chaplygin gas

“…This model incorporates an extra parameter which is associated to a lower bound on the sound speed of the effective DM component. The MCG has been observationally constrained using the redshift dependence of the apparent magnitude of type Ia supernovae, the Cosmic Microwave Background (CMB) anisotropies, and the matter power spectrum, including Baryonic Acoustic Oscillations (BAO) [25][26][27][28][29][30][31][32][33][34]. Further extensions incorporating additional terms accounting for a possible growth of the comoving Jeans length with cosmic density have also been proposed in the literature (see, e.g., [35]).…”