Singh, Ashutosh Chaubey, R.
Published in
Astrophysics and Space Science

In this article, we examine the solution for expanding cosmology, which imitates properties similar to an interplay of dark matter and dark energy. The effective fluid of this toy model may behaves like dust matter at early epoch and as a cosmological constant at later epoch. Also, for this solution, the cosmological parameters are calculated and t...

Mishra, R. K. Dua, Heena
Published in
Astrophysics and Space Science

This study aims to examine the dynamics of flat Friedmann-Lemaitre-Robertson-Walker (FLRW) model of universe with time varying cosmological constant Λ(t)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddside...

Singh, Ashutosh
Published in
Astrophysics and Space Science

A flat Friedmann-Robertson-Walker (FRW) cosmological model with perfect fluid has been investigated within the framework of the particle creation mechanism. Perfect fluid isentropic particle creation rate as a function of Hubble parameter has been incorporated. By considering a simple parametrization of Hubble parameter, we discuss the cosmological...

Bakry, M. A. Shafeek, Aryn T.
Published in
Astrophysics and Space Science

In the present paper, we propose a new law for the deceleration parameter of the second degree of the time. Our law tells us about the behavior of the universe. According to our law, the spatially closed, flat and open universes are allowed, and the universe passes through with a big-rip and then retreats as it was in the moment of the big bang. Th...

Nair, K. Rajagopalan Mathew, Titus K.
Published in
Astrophysics and Space Science

Many have speculated about the presence of a stiff fluid in very early stage of the universe. Such a stiff fluid was first introduced by Zel’dovich. Recently the late acceleration of the universe was studied by taking bulk viscous stiff fluid as the dominant cosmic component, but the age predicted by such a model is less than the observed value. We...

Azri, Hemza Bounames, A.

We derive a model of dark energy which evolves with time via the scale factor. The equation-of-state is studied as a function of a parameter α introduced in this model as = (1 - 2α)/(1 + 2α). In addition to the recent accelerated expansion, the model predicts another decelerated phase. These two phases are studied via the parameter α. The age of th...

Paul, Bikash Chandra Thakur, Prasenjit
Published in
Astrophysics and Space Science

We investigate emergent universe model using recent observational data of the background as well as the growth tests. The flat emergent universe model obtained by Mukherjee et al. is permitted with a non-linear equation of state (in short, EoS) (p=Aρ−Bρ12\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \...

Paul, Bikash Chandra Thakur, Prasenjit Beesham, Aroon
Published in
Astrophysics and Space Science

We study cosmological models with modified Chaplygin gas (MCG) to determine observational constraints on its EoS parameters using the background and the growth tests data. The background test data consists of H(z)−z\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} ...

Farmany, A. Mortazavi, S. S.
Published in
Astrophysics and Space Science

In this paper, minimal length uncertainty is used as a constraint to solve the Friedman equation. It is shown that, based on the minimal length uncertainty principle, the Hubble scale is decreasing which corresponds to an accelerating universe.

Nashed, G. L.
Published in
General Relativity and Gravitation

We derive asymptote solution of a homogeneous and isotropic universe governed by the quadratic form of the field equation of f(T) gravity. We explain how the higher order of the torsion can provide an origin for late accelerated phase of the universe in the FRW. The solution makes the scalar torsion T to be a function of the cosmic time t. We show ...