Modified Chaplygin gas cosmology with observational constraints

摘要

The spatially homogeneous and totally anisotropic Bianchi type-II space-time models with modified Chaplygin gas having the equation of state p=Aρ−Bρα, 0 ≤ A ≤ 1, 0 ≤ α ≤ 1, where A, α and B are positive constants, have been investigated. It has been shown that the equation of state for such modified model is valid from the radiation era to the ΛCDM. The statefinder, which is the cosmological diagnostic pair {r, s} has been adopted to characterize different phases of the universe. The physical and geometrical properties of the corresponding cosmological models have been discussed. The observational constraints, essentially dependent on the hubble parameter H0 and deceleration parameter q0 have been investigated using 28 data points of H(z), SNe Ia and H(z)+ SNe Ia [57]. It has been seen that the average scale factor a(t) can be expanded in terms of an infinite convergent series around the current value of the average scale factor a0 using Taylor’s theorem, in which the current value of the deceleration parameter q0, the dimensionless jerk parameter j0, the snap parameter s0* and the lerk parameter ℓ0 appeared.