BIANCHITYPE-V COSMOLOGICAL MODELS OF THE UNIVERSE FOR BULK VISCOUS FLUID DISTRIBUTION IN GENERAL RELATIVITY: EXPRESSIONS FOR SOME OBSERVABLE QUANTITIES

摘要

A new class of a spatially homogeneous and anisotropic Bianchi type-V cosmological models of the Universe for bulk viscous fluid distribution within the framework of general relativity is investigated by applying the law of variation for the generalized mean Hubble's parameter that yields a constant value of deceleration parameter. The variation for Hubble's parameter generates two types of solutions for the average scale factor one is of power-law type and other is of the exponential form. Using these two forms, Einstein's field equations are solved separately that correspond to singular and non-singular models of the Universe respectively. It is observed that for positive value of deceleration parameter q of the Universe decelerates whereas for negative value of q the Universe accelerates. Expressions for look-back time-redshift, neoclassical tests (proper distance d(z)), luminosity distance red-shift and event horizon are derived and their significance are described in detail. Some physical and geometrical properties of the models are also discussed.