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 , \Omega _ { b } h ^ { 2 } = 0.02263 ^ { +0.00184 } _ { -0.00162 } ( 1 \sigma ) ^ { +0.00213 } _ { -0.00195 } ( 2 \sigma ) , B _ { s } = 0.7788 ^ { +0.0736 } _ { -0.0723 } ( 1 \sigma ) ^ { +0.0918 } _ { -0.0904 } ( 2 \sigma ) , \alpha = 0.1079 ^ { +0.3397 } _ { -0.2539 } ( 1 \sigma ) ^ { +0.4678 } _ { -0.2911 } ( 2 \sigma ) , B = 0.00189 ^ { +0.00583 } _ { -0.00756 } ( 1 \sigma ) ^ { +0.00660 } _ { -0.00915 } ( 2 \sigma ) , and H _ { 0 } = 70.711 ^ { +4.188 } _ { -3.142 } ( 1 \sigma ) ^ { +5.281 } _ { -4.149 } ( 2 \sigma ) .