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Related papers: Singularity free stars in (2+1) dimensions

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We study nonaxisymmetric perturbations of rotating relativistic stars. modeled as perfect-fluid equilibria. Instability to a mode with angular dependence $\exp(im\phi)$ sets in when the frequency of the mode vanishes. The locations of these…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Nikolaos Stergioulas , John L. Friedman

We study isotropic and anisotropic (Bianchi I) cosmologies in Palatini $f(R)$ and $f(R,R_{\mu\nu}R^{\mu\nu})$ theories of gravity and consider the existence of non-singular bouncing solutions in the early universe. We find that all $f(R)$…

General Relativity and Quantum Cosmology · Physics 2014-11-21 Carlos Barragan , Gonzalo J. Olmo

We investigate the properties of anisotropic, spherically symmetric compact stars, especially neutron stars and strange quark stars, made of strongly magnetized matter. The neutron stars are described by SLy equation of state, the strange…

High Energy Astrophysical Phenomena · Physics 2021-12-08 Debabrata Deb , Banibrata Mukhopadhyay , Fridolin Weber

We present new anisotropic generalization of Buchdahl [1] type perfect fluid solution by using the method of earlier work [2]. In similar approach we have constructed the new pressure anisotropy factor ${\Delta}$ by the help both the metric…

General Relativity and Quantum Cosmology · Physics 2015-11-26 S. K. Maurya , Y. K. Gupta , Baiju Dayanandan , M. K. Jasim , Ahmed Al-Jamel

Non-radial oscillation modes of neutron stars serve as diagnostics of their internal composition and relativistic structure. In this work, we investigate the perturbations of static and spherically symmetric neutron stars characterized by…

General Relativity and Quantum Cosmology · Physics 2026-05-08 Jose F. Rodriguez-Ruiz , L. M. Becerra , F. D. Lora-Clavijo

Anisotropic cosmological models such as the G\"{o}del universe and its extensions - G\"{o}del type solutions, are embedded on a visible 3-brane in the Randall-Sundrum 1 model. The size of the extra dimension is stabilized by tuning the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Moninder Singh Modgil , Sukanta Panda

Motivated by the recent suggestions that very massive pulsar (PSR J0952-0607) and very light compact object (HESS J1731-347) exist, in this article, we revisit the possibility of such objects being strange stars instead of the standard…

High Energy Astrophysical Phenomena · Physics 2023-09-06 H. C. Das , Luiz L. Lopes

The present study deals with spatially homogeneous and totally anisotropic locally rotationally symmetric (LRS) Bianchi type I cosmological model with variable $G$ and $\Lambda$ in presence of imperfect fluid. To get the deterministic model…

General Physics · Physics 2012-01-17 Anil Kumar Yadav , Anirudh Pradhan , Ajay Kumar Singh

We study static, spherically symmetric neutron stars in a class of scalar-tensor theories with non-canonical kinetic terms (K-essence) obeying all causality and hyperbolicity conditions. These models have non-trivial dynamics that lead to a…

General Relativity and Quantum Cosmology · Physics 2025-09-12 Mark P. Hertzberg , Oleksandr S. Stashko

We address the problem of finding static and spherically symmetric anisotropic compact stars in general relativity that admit conformal motions. The study is framed in the language of f(R) gravity theory in order to expose opportunity for…

General Relativity and Quantum Cosmology · Physics 2017-07-06 Ayan Banerjee , Sumita Banerjee , Sudan Hansraj , Ali Ovgun

We study nature of singularities in anisotropic string-inspired cosmological models in the presence of a Gauss-Bonnet term. We analyze two string gravity models-- dilaton-driven and modulus-driven cases-- in the Bianchi type-I background…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Alexey Toporensky , Shinji Tsujikawa

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

We apply an extended version of the SU(3) parity model, containing quark degrees of freedom, to study neutron stars. The model successfully reproduces the main thermodynamic features of QCD which allows us to describe the composition of…

High Energy Astrophysical Phenomena · Physics 2015-06-05 V. Dexheimer , J. Steinheimer , R. Negreiros , S. Schramm

This work aims to investigate the behaviour of compact stars in the background of $f(R, T)$ theory of gravity. For current work, we consider the Krori-Barua metric potential i.e., $\nu(r)= Br^2+C$ and $\lambda(r)= Ar^2,$ where, $A, B$ and…

General Relativity and Quantum Cosmology · Physics 2023-04-13 M. Farasat Shamir , Zoya Asghar , Adnan Malik

In this paper, we study the physical characteristics of anisotropic spherically symmetric quark star candidates for $R+2\sigma T$ gravity model, where $R$, $\sigma$ and $T$ depict scalar curvature, coupling parameter, and the trace of the…

General Relativity and Quantum Cosmology · Physics 2020-01-08 M. Sharif , Arfa Waseem

We derive upper and lower limits for the basic physical parameters (mass-radius ratio, anisotropy, redshift and total energy) for arbitrary anisotropic general relativistic matter distributions in the presence of a cosmological constant.…

General Relativity and Quantum Cosmology · Physics 2007-05-23 C. G. Boehmer , T. Harko

This article focuses on different anisotropic models within the framework of a specific modified $f(\mathcal{R},\mathcal{T},\mathcal{R}_{\zeta\gamma}\mathcal{T}^{\zeta\gamma})$ gravity theory. The study adopts a static spherically symmetric…

General Relativity and Quantum Cosmology · Physics 2025-04-22 Yihu Feng , Tayyab Naseer , G. Mustafa , S. K. Maurya

We propose a relativistic model for quintessence stars with the combination of an anisotropic pressure corresponding to normal matter and a quintessence dark energy having a characteristic parameter {\omega}q such that -1 <{\omega}q < -…

General Relativity and Quantum Cosmology · Physics 2015-06-16 Mehedi Kalam , Farook Rahaman , Sajahan Molla , Sk. Monowar Hossein

We investigate dynamics of (4+1) and (5+1) dimensional flat anisotropic Universe filled by a perfect fluid in the Gauss-Bonnet gravity. An analytical solutions valid for particular values of the equation of state parameter $w=1/3$ have been…

General Relativity and Quantum Cosmology · Physics 2014-11-20 I. V. Kirnos , A. N. Makarenko , S. A. Pavluchenko , A. V. Toporensky

By assuming a particular mass function we find new exact solutions to the Einstein field equations with an anisotropic matter distribution. The solutions are shown to be relevant for the description of compact stars. A distinguishing…

General Relativity and Quantum Cosmology · Physics 2008-11-26 R. Sharma , S. D. Maharaj