Cosmological constant dominated transit universe from early deceleration to current acceleration phase in Bianchi-V space-time

Abstract

The paper presents the transition of universe from early decelerating phase to current accelerating phase with viscous fluid and time dependent cosmological constant $(\Lambda)$ as source of matter in Bianchi-V space-time. To study the transit behaviour of universe, we have assumed the scale factor as increasing function of time which generates a time dependent deceleration parameter (DP). The study reveals that the cosmological term does not change its fundamental nature for $\xi$ = constant and $\xi=\xi(t)$, where $\xi$ is the coefficient of bulk viscosity. The $\Lambda(t)$ is found to be positive and is decreasing function of time. The same is observed by recent supernovae observations. The physical behaviour of universe has been discussed in detail.