scholarly journals Charged anisotropic matter with a linear equation of state

2008 ◽  
Vol 25 (23) ◽  
pp. 235001 ◽  
Author(s):  
S Thirukkanesh ◽  
S D Maharaj
Keyword(s):  
Equation Of State ◽  
Linear Equation ◽  
Anisotropic Matter

Existence of realistic stellar objects in Rastall gravity with linear equation of state

2020 ◽  
Vol 98 (5) ◽  
pp. 464-469
Author(s):  
M. Zubair ◽  
Maham Lodhi ◽  
G. Abbas ◽  
Mehwish Bari
Keyword(s):  
Equation Of State ◽  
Linear Equation ◽  
Anisotropy Parameter ◽  
Compact Objects ◽  
Physical Analysis ◽  
Dynamical Equations ◽  
Stellar Objects ◽  
Anisotropic Matter ◽  
Spherically Symmetric Metric ◽  
Acceptability Criteria

In this paper, we have discussed the anisotropic matter configuration to explore the existence of realistic stellar objects in non-conservative theory named as Rastall theory of gravity. We have assumed a static spherically symmetric metric with linear equation of state (EoS) to formulate the dynamical equations. The Durgapal and Banerji transformation is employed to investigate the gravitational behavior of compact objects. In this regard, a particular gravitational potential is selected to solve the system of dynamical equations numerically. We compared change in behavior of physical quantities like energy density, anisotropy parameter, and radial and tangential pressures by plotting three particular cases. With the help of physical analysis, it can be seen that the solutions of compact spheres hold physical acceptability criteria and depict stability.

scholarly journals Emergent Universe as an interaction in the dark sector

2017 ◽  
Vol 32 (28) ◽  
pp. 1750152
Author(s):  
Emiliano Marachlian ◽  
I. E. Sánchez G. ◽  
Osvaldo P. Santillán
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Equation Of State ◽  
Linear Equation ◽  
Vacuum Energy ◽  
Cosmological Parameters ◽  
Emergent Universe ◽  
Dark Sector ◽  
Cosmological Scenario ◽  
Friedmann Robertson Walker

A cosmological scenario where dark matter interacts with a variable vacuum energy for a spatially flat Friedmann–Robertson–Walker (FRW) spacetime is proposed and analyzed to show that with a linear equation of state and a particular interaction in the dark sector it is possible to get a model of an Emergent Universe. In addition, the viability of two particular models is studied by taking into account the recent observations. The updated observational Hubble data and the JLA supernovae data are used in order to constraint the cosmological parameters of the models and estimate the amount of dark energy in the radiation era. It is shown that the two models fulfil the severe bounds of [Formula: see text] at the 2[Formula: see text] level of Planck.

Stability of generalized polytropic models

2019 ◽  
Vol 16 (04) ◽  
pp. 1950056
Author(s):  
I. Nazir ◽  
M. Azam
Keyword(s):  
Equation Of State ◽  
Local Density ◽  
Hydrostatic Equilibrium ◽  
Physical Parameters ◽  
Spherically Symmetric ◽  
Anisotropic Matter ◽  
Polytropic Equation ◽  
Density Perturbations ◽  
Radial Forces ◽  
The Stability

In this paper, we have investigated the stability of a spherically symmetric object with charged anisotropic matter by using the concept of cracking. The cracking is a very intuitive technique to check the stability which is based on the analysis of the radial forces that appear on the system due to perturbations taking it out of its equilibrium state. For this, we have applied and studied the effect of local density perturbations to the hydrostatic equilibrium equation and on all the physical parameters with generalized polytropic equation of state. It is found that some of the generalized polytropic models exhibit cracking.

Bouncing scenario in Brans–Dicke theory

2020 ◽  
Vol 17 (04) ◽  
pp. 2050056
Author(s):  
Sunil Kumar Tripathy ◽  
Subingya Pandey ◽  
Alaka Priyadarsini Sendha ◽  
Dipanjali Behera
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Equation Of State ◽  
Linear Equation ◽  
Scale Factor ◽  
Cosmic Acceleration ◽  
Late Time ◽  
Dark Fluid

A bouncing scenario is studied in the framework of generalized Brans–Dicke theory. In order to have a dark energy (DE) driven late time cosmic acceleration, we have considered a unified dark fluid simulated by a linear equation of state (EoS). The evolutionary behavior of the DE equation of parameter derived from the unified dark fluid has been discussed. The effect of the bouncing scale factor on the Brans–Dicke parameter, self-interacting potential and the Brans–Dicke scalar field is investigated.

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