Generalized Chaplygin gas model: Constraints from Hubble parameter versus redshift data

We examine observational constraints on the generalized Chaplygin gas (GCG) model for dark energy from the 9 Hubble parameter data points, the 115 SNLS Sne Ia data and the size of baryonic acoustic oscillation peak at redshift, z=0.35z=0.35. At a 95.4% confidence level, a combination of three data sets gives 0.67⩽As⩽0.830.67⩽As⩽0.83 and −0.21⩽α⩽0.42−0.21⩽α⩽0.42, which is within the allowed parameters ranges of the GCG as a candidate of the unified dark matter and dark energy. It is found that the standard Chaplygin gas model (α=1α=1) is ruled out by these data at the 99.7% confidence level.