We use the Markov Chain Monte Carlo method to investigate a global constraints on the generalized Chaplygin gas ( GCG ) model as the unification of dark matter and dark energy from the latest observational data : the Constitution 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 non-flat universe , the constraint results for GCG model are , \Omega _ { b } h ^ { 2 } = 0.0235 ^ { +0.0021 } _ { -0.0018 } ( 1 \sigma ) ^ { +0.0028 } _ { -0.0022 } ( 2 \sigma ) , \Omega _ { k } = 0.0035 ^ { +0.0172 } _ { -0.0182 } ( 1 \sigma ) ^ { +0.0226 } _ { -0.0204 } ( 2 \sigma ) , A _ { s } = 0.753 ^ { +0.037 } _ { -0.035 } ( 1 \sigma ) ^ { +0.045 } _ { -0.044 } ( 2 \sigma ) , \alpha = 0.043 ^ { +0.102 } _ { -0.106 } ( 1 \sigma ) ^ { +0.134 } _ { -0.117 } ( 2 \sigma ) , and H _ { 0 } = 70.00 ^ { +3.25 } _ { -2.92 } ( 1 \sigma ) ^ { +3.77 } _ { -3.67 } ( 2 \sigma ) , which is more stringent than the previous results for constraint on GCG model parameters .
Furthermore , according to the information criterion , it seems that the current observations much support \Lambda CDM model relative to the GCG model .