Related papers: Viscous universe with cosmological constant
Despite the many efforts, our theoretical understanding of the ultimate nature of the dark energy component of the universe still lags well behind the astounding experimental evidence achieved from the increasingly sophisticated…
With the motivation in mind to evaluate the contribution of the cosmological constant $\Lambda$ on the foam like patterns formation process in the distribution of galaxies, we investigate the Newtonian dynamics of a spherical void embedded…
Recently there have been claims on model-independent evidence of dynamical dark energy. Herein we consider a fairly general class of cosmological models with a time-evolving cosmological term of the form $\Lambda(H)=C_0+C_H H^2+C_{\dot{H}}…
In this work, we have studied how incorporating viscous fluids leads to exact bounce cosmological solutions in general relativity (GR) framework. Specifically, we propose a novel parameterization of bulk viscosity coefficient of the form…
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…
The increasing precision in the determination of the Hubble parameter has reached a per cent level at which large-scale cosmic flows induced by inhomogeneities of the matter distribution become non-negligible. Here we use large-scale…
In this article, we investigate the observed cosmic acceleration in the framework of a cosmological $f(R,L_m)$ model dominated by bulk viscous matter in an anisotropic background. We consider the LRS Bianchi type I metric and derive the…
Bianchi type III string cosmological models with bulk viscous fluid for massive string are investigated. To get the determinate model of the universe, we have assumed that the coefficient of bulk viscosity ($\xi$) is inversely proportional…
In this paper, we have investigated late time acceleration for a spatially flat dust filled Universe in Brans-Dicke theory in the presence of a positive cosmological constant $\Lambda$ . Expressions for Hubble's constant, luminosity…
Spatially homogeneous and anisotropic Bianchi type V space-time with bulk viscous fluid source and time varying gravitational constant $G$ and cosmological term $\Lambda$ are considered. Coefficient of bulk viscosity $\zeta$ is assumed as a…
Recent observations of high-redshift supernovae seem to suggest that the global geometry of the Universe may be affected by a `cosmological constant', which acts to accelerate the expansion rate with time. But these data by themselves still…
We present a novel extended version of the $\Lambda$CDM model that provides analytical solution for Hubble parameter uniting all epochs of cosmic evolution starting from inflation to late-acceleration, with intermediate radiation and…
In this work we study the evolution of a spatially flat Universe by considering a viscous dark matter and perfect fluids for dark energy and radiation, including an interaction term between dark matter and dark energy. In the first part, we…
The Standard Cosmological Model has experienced tremendous success at reproducing observational data by assuming a universe dominated by a cosmological constant and dark matter in a flat geometry. However, several studies, based on local…
One of the fundamental assumptions of the standard $\Lambda$CDM cosmology is that, on large scales, all the matter-energy components of the Universe share a common rest frame. This seems natural for the visible sector, that has been in…
Based on the assumption that the dark energy possessing bulk viscosity is homogenously and isotropically permeated in the universe, we propose three new viscous dark energy (VDE) models to characterize the accelerating universe. By…
We propose a new model for the viscosity of cosmic matters, which can be applied to different epochs of the universe. Using this model, we include the bulk viscosities as practical corrections to the perfect fluid models of the baryonic and…
In the present paper, the effects of viscous dark matter are analysed within the $\Lambda$CDM model. Here we consider bulk viscosity through the Israel-Stewart theory approach, leading to an effective pressure term in the continuity…
We consider a unified dissipative dark fluid model. Our fluid contains an adiabatic part plus a bulk viscous one. The adiabatic part has the ability to asymptote between two power laws and so can interpolate between the dust and dark energy…
We discuss a cosmology in which cold dark-matter particles decay into relativistic particles. We argue that such decays could lead naturally to a bulk viscosity in the cosmic fluid. For decay lifetimes comparable to the present hubble age,…