English
Related papers

Related papers: Slowly-Rotating Neutron Stars in Massive Bigravity

200 papers

We present the first numerical models of differentially rotating stars in alternative theories of gravity. We chose a particular class of scalar-tensor theories of gravity that is indistinguishable from GR in the weak field regime but can…

General Relativity and Quantum Cosmology · Physics 2018-12-05 Daniela D. Doneva , Stoytcho S. Yazadjiev , Nikolaos Stergioulas , Kostas D. Kokkotas

We perform fully relativistic calculations of binary neutron stars in quasi-equilibrium circular orbits. We integrate Einstein's equations together with the relativistic equation of hydrostatic equilibrium to solve the initial value problem…

General Relativity and Quantum Cosmology · Physics 2009-10-30 T. W. Baumgarte , G. B. Cook , M. A. Scheel , S. L. Shapiro , S. A. Teukolsky

Neutron stars are the densest objects known in the Universe. Being the final product of stellar evolution, their internal composition and structure is rather poorly constrained by measurements. It is the purpose of this paper to put some…

High Energy Astrophysical Phenomena · Physics 2015-05-19 J. Petri

We calculate the disk and boundary layer luminosities for accreting rapidly rotating neutron stars with low magnetic fields in a fully general relativistic manner. Rotation increases the disk luminosity and decreases the boundary layer…

Astrophysics · Physics 2007-05-23 Arun V. Thampan , Bhaskar Datta

Quartic gravity theory is considered with the Einstein-Hilbert Lagrangean $R+aR^{2}+bR_{\mu \nu}R^{\mu \nu},$ $R_{\mu \nu}$ being Ricci\'s tensor and R the curvature scalar. The parameters $a$ and $b$ are taken of order 1 km$^{2}.$…

General Relativity and Quantum Cosmology · Physics 2021-06-16 Emilio Santos

We analyze numerically the dynamical transition to spontaneous scalarization in neutron stars in the framework of a scalar-tensor theory of gravity where the scalar field is free but massive, and it is coupled nonminimally to gravity in the…

General Relativity and Quantum Cosmology · Physics 2024-10-04 Juan Carlos Degollado , Néstor Ortiz , Marcelo Salgado

We investigate the effects of relativity on the gravitational instability of finite isothermal gaseous spheres. In the first part of the paper, we treat the gravitational field within the framework of Newtonian mechanics but we use a…

Astrophysics · Physics 2009-11-07 Pierre-Henri Chavanis

We have computed quasiequilibrium sequences of synchronously rotating compact binary star systems with constant rest masses. This computation has been carried out by using the numerical scheme which is different from the scheme based on the…

Astrophysics · Physics 2009-11-07 Fumihiko Usui , Yoshiharu Eriguchi

We investigated realistic neutron stars in axion $R^{2}$ gravity. The coupling between curvature and axion field $\phi$ is assumed in the simple form $\sim R^2\phi$. For the axion mass in the range $m_{a}\sim 10^{-11}-10^{-10}$ eV the…

General Relativity and Quantum Cosmology · Physics 2020-01-29 Artyom V. Astashenok , Sergey D. Odintsov

We calculate static and spherically symmetric solutions for the Rastall modification of gravity to describe Neutron Stars (NS). The key feature of the Rastall gravity is the non-conservation of the energy-momentum tensor proportionally to…

General Relativity and Quantum Cosmology · Physics 2016-10-24 A. M. Oliveira , H. E. S. Velten , J. C. Fabris , L. Casarini

We present new results on dynamical instabilities in rapidly rotating neutron-stars. In particular, using numerical simulations in full General Relativity, we analyse the effects that the stellar compactness has on the threshold for the…

Astrophysics · Physics 2008-11-26 G. M. Manca , L. Baiotti , R. De Pietri , L. Rezzolla

The structure of neutron stars is considered from theoretical and observational perspectives. We demonstrate an important aspect of neutron star structure: the neutron star radius is primarily determined by the behavior of the pressure of…

Astrophysics · Physics 2008-11-26 J. M. Lattimer , M. Prakash

Neutron stars are the most compact horizonless objects in the Universe, exhibiting the strongest known magnetic fields. They are potential sources of coincident gravitational waves and electromagnetic radiation across the entire spectrum.…

High Energy Astrophysical Phenomena · Physics 2025-08-29 Fabrizio Venturi Piñas , Anson Ka Long Yip , Patrick Chi-Kit Cheong , Milton Ruiz

We present analytic solutions of Maxwell equations in the internal and external background spacetime of a slowly rotating magnetized neutron star. The star is considered isolated and in vacuum, with a dipolar magnetic field not aligned with…

Astrophysics · Physics 2009-10-31 L. Rezzolla , B. J. Ahmedov , J. C. Miller

In the context of f(R) gravity theories, we show that the apparent mass of a neutron star as seen from an observer at infinity is numerically calculable but requires careful matching, first at the star's edge, between interior and exterior…

General Relativity and Quantum Cosmology · Physics 2016-09-14 Miguel Aparicio Resco , Alvaro de la Cruz-Dombriz , Felipe J. Llanes-Estrada , Victor Zapatero Castrillo

Spherical neutron star models are studied within tensor-scalar theories of gravity. Particularly, it is shown that, under some conditions on the second derivative of the coupling function and on star's mass, for a given star there exist two…

General Relativity and Quantum Cosmology · Physics 2009-10-31 J. Novak

The influence of the rotation on the total masses and radii of the neutron stars are calculated by the Hartle's slow rotation formalism, while the equation of state is considered in a relativistic $\sigma-\omega$ model. Comparing with the…

Astrophysics · Physics 2009-11-10 De-hua Wen , Wei Chen , Xian-ju Wang , Bao-quan Ai , Guo-tao Liu , Dong-qiao Dong , Liang-gang Liu

This study investigates the modeling of anisotropic magnetized static neutron stars within the framework of five-dimensional Einstein-Gauss-Bonnet (5D EGB) gravity. While Einstein's gravity has traditionally been employed to examine neutron…

General Relativity and Quantum Cosmology · Physics 2025-08-21 Mohammad Mazhari

We present a self-consistent, relativistic model of rapidly rotating neutron stars describing their exterior gravitational field. This is achieved by matching the new solution of Einstein's field equations found by Manko et al. (2000) and…

Astrophysics · Physics 2009-11-07 Matthias Stute , Max Camenzind

We study the existence and structure of static and slowly rotating neutron stars (NSs) in a particular truncation of scalar torsion theory with a scalar field $ \phi $ non-minimally coupled to the torsion scalar, and a potential of the form…

General Relativity and Quantum Cosmology · Physics 2024-12-31 Youcef Kehal , Khireddine Nouicer , Hamza Boumaza