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This paper deals with isothermal Euler-Poisson system which is used to model collapse of self-gravitating Newtonian star. Density dependent viscosity term is added on the right-hand side of momentum equation and it has been proved that…

Analysis of PDEs · Mathematics 2025-08-19 Marko Nedeljkov , Sanja Ružičić

For static fluid spheres, the condition of hydrostatic equilibrium is given by the generalized Tolman--Oppenheimer--Volkoff (TOV) equation, a Riccati equation in the radial pressure. For a perfect fluid source, it is known that finding a…

General Relativity and Quantum Cosmology · Physics 2021-09-01 M M Akbar , R Solanki

We study spherically symmetric solutions with a scalar field in the shift-symmetric subclass of the Horndeski theory. Constructing an effective energy-momentum tensor of the scalar field based on the two-fluid model, we decompose the scalar…

General Relativity and Quantum Cosmology · Physics 2020-10-13 Jiaming Shi , Taishi Katsuragawa , Taotao Qiu

We examine the behaviour of homogeneous, anisotropic space-times, specifically the locally rotationally symmetric Bianchi types $I$ and $VII_o$ in the presence of anisotropic matter. By finding an appropriate constant of the motion, and…

General Relativity and Quantum Cosmology · Physics 2016-04-29 David Sloan

Concerning the stability of two-fluid star models, we prove the rigorous equivalence of two independent determining methods for mixed stars, after a brief review of the hybrid star case. Our derivations apply to general multi-fluid cases,…

High Energy Astrophysical Phenomena · Physics 2025-12-02 Xiao-Ding Zhou , Tian-Shun Chen , Si-Man Wu , Kilar Zhang

In the current article, we study anisotropic spherically symmetric strange star under the background of $f(R,T)$ gravity using the metric potentials of Tolman-Kuchowicz type~\cite{Tolman1939,Kuchowicz1968} as $\lambda(r)=\ln(1+ar^2+br^4)$…

General Relativity and Quantum Cosmology · Physics 2020-06-03 Suparna Biswas , Dibyendu Shee , B. K. Guha , Saibal Ray

This paper constructs two immediate extensions of the existing anisotropic solutions in the context of Einstein-Maxwell framework by employing minimal geometric deformation. To achieve this, we assume a static spherical interior initially…

General Relativity and Quantum Cosmology · Physics 2023-10-03 M. Sharif , Tayyab Naseer

In the context of the study of the properties of the mutual mass distribution of the bright and dark matter in elliptical galaxies, present a family of two-component, spherical, self-consistent galaxy models, where one density distribution…

Astrophysics · Physics 2009-10-31 L. Ciotti

We provide new exact solutions to the Einstein-Maxwell system of equations which are physically reasonable. The spacetime is static and spherically symmetric with a charged matter distribution. We utilise an equation of state which is…

General Relativity and Quantum Cosmology · Physics 2015-06-12 S. D. Maharaj , P. Mafa Takisa

The main purpose of this paper is to obtain physically stable stellar models coupled with anisotropic matter distribution in the context of $f(\mathcal{R},\mathrm{T}^{2})$ theory. For this, we consider a static spherical geometry and…

General Relativity and Quantum Cosmology · Physics 2024-06-06 Tayyab Naseer , M. Sharif , Sana Manzoor , Arooj Fatima

In this work, we generate two static anisotropic solutions for a sphere containing quark matter in the framework of self-interacting Brans-Dicke theory. For this purpose, we add an anisotropic source in the seed distribution and decouple…

General Relativity and Quantum Cosmology · Physics 2023-07-26 M. Sharif , Amal Majid

We consider spherically symmetric spacetimes sourced by a fluid with pressure anisotropy in the radial direction. We use gauge-invariant perturbation theory to study the stability of this class of spacetimes under axial perturbations. We…

General Relativity and Quantum Cosmology · Physics 2014-07-23 Bhavesh Khamesra , V Suneeta

After deducing the density profiles and gravitational potential functions of eight galaxies from the rotation velocity data from THINGS, we find that the density decreases exponentially with the potential in substantial regions of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Joshua Davidson , Sanjoy K. Sarker , Allen Stern

Galaxies exhibit a variety of non-axisymmetric structure (bars, spiral structure, lopsided structure, etc.). These suggest the following general problem: what are the possible stationary configurations of a two-dimensional self-gravitating…

Astrophysics · Physics 2015-06-24 Dave Syer , Scott Tremaine

In the background of a homogeneous and isotropic spacetime with zero spatial curvature, we consider interacting scenarios between two barotropic fluids, one is the pressureless dark matter (DM) and the other one is dark energy (DE), in…

General Relativity and Quantum Cosmology · Physics 2017-02-01 German S. Sharov , Subhra Bhattacharya , Supriya Pan , Rafael C. Nunes , Subenoy Chakraborty

Since the discovery of the accelerated expansion of the universe, it was necessary to introduce a new component of matter distribution called dark energy. The standard cosmological model considers isotropy of the pressure and assumes an…

General Relativity and Quantum Cosmology · Physics 2012-10-25 R. Chan , M. F. A. da Silva , J. F. Villas da Rocha

We obtain a mass function solving the Tolman-Oppenheimer-Volkoff (TOV) equation for isotropic and spherically symmetric system via homotopy perturbation method (HPM). Using the mass function we construct a stellar model which can be…

General Relativity and Quantum Cosmology · Physics 2019-11-04 Abdul Aziz , Saibal Ray , Farook Rahaman , B. K. Guha

This paper explores the viability and stability of compact stellar objects characterized by anisotropic matter in the framework of $f(\mathrm{Q},\mathrm{T})$ theory, where $\mathrm{Q}$ denotes non-metricity and $\mathrm{T}$ represents the…

General Relativity and Quantum Cosmology · Physics 2024-07-08 M. Zeeshan Gul , M. Sharif , Adeeba Arooj

In this paper we study the evolution of the dark energy parameter within the scope of a spatially homogeneous and isotropic Friedmann-Robertson-Walker (FRW) model filled with barotropic fluid and dark energy by revisiting the recent results…

General Relativity and Quantum Cosmology · Physics 2015-05-01 Bijan Saha , Hassan Amirhashchi , Anirudh Pradhan

In the present work, we have searched the existence of anisotropic and non-singular compact star in the $f(R,T)$ gravity by taking into account the non-exotic equation of state (EoS). In order to obtain the solutions of the matter content…

General Relativity and Quantum Cosmology · Physics 2020-07-02 Anil Kumar Yadav , Monimala Mondal , Farook Rahaman