CONSTRAINTS ON VARIABLE CHAPLYGIN GAS MODEL FROM TYPE IA SUPERNOVAE AND BARYON ACOUSTIC OSCILLATIONS

We apply the type Ia supernovae union dataset and the baryon acoustic oscillations data at z = 0.2 and z = 0.35 to constrain variable Chaplygin gas (VCG) model as the unification of dark matter and dark energy. It is shown that the confidence levels for VCG model parameters are B-s = 0.075(0.013)(+0.016)(1 sigma) (+0.026)(0.020)(2 sigma), n = 1.30(0.049)(+0.46) (1 sigma) (+0.74)(-0.81)(2 sigma) . And it indicates that the values of transition redshift and current deceleration parameter are: z(T) = 0.74(-0.05)(+0.05) (1 sigma), q(0) = -0.54(-0.07)(+0.07)(1 sigma). In addition, we plot the evolution trajectory of the VCG model in the statefinder parameter r-s plane and show the discrimination between this scenario and other dark energy models.