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Related papers: Isolated and Binary Neutron Stars in Dynamical Che…

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Dynamical Chern-Simons gravity cannot be strongly constrained with current experiments because it reduces to General Relativity in the weak-field limit. This theory, however, introduces modifications in the non-linear, dynamical regime, and…

General Relativity and Quantum Cosmology · Physics 2020-01-03 Kent Yagi , Nicolas Yunes , Takahiro Tanaka

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 model two mergers of orbiting binary neutron stars, the first forming a black hole and the second a differentially rotating neutron star. We extract gravitational waveforms in the wave zone. Comparisons to a post-Newtonian analysis allow…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Matthew Anderson , Eric W. Hirschmann , Luis Lehner , Steven L. Liebling , Patrick M. Motl , David Neilsen , Carlos Palenzuela , Joel E. Tohline

Neutron stars are ideal to probe, not only nuclear physics, but also strong-field gravity. Approximate universal relations insensitive to the star's internal structure exist among certain observables and are useful in testing General…

General Relativity and Quantum Cosmology · Physics 2017-12-27 Toral Gupta , Barun Majumder , Kent Yagi , Nicolás Yunes

We present a new numerical scheme for solving the initial value problem for quasiequilibrium binary neutron stars allowing for arbitrary spins. We construct sequences of circular-orbit binaries of varying separation, keeping the rest mass…

General Relativity and Quantum Cosmology · Physics 2016-11-09 P. Marronetti , S. L. Shapiro

In this paper, we study the slowly rotating neutron stars in $f(R, T)$ gravity based on Hartle-Thorne formalism. We first consider the simplest matter-geometry coupled modified gravity, namely $f(R, T)=R+2\chi T$. We compute the mass,…

General Relativity and Quantum Cosmology · Physics 2024-09-16 Masum Murshid , Mehedi Kalam

We present and discuss the possibility, derived from work carried out 20 years ago, that the equations of motion for compact binary neutron stars at the third post-Newtonian (3PN) order in general relativity might actually depend on the…

General Relativity and Quantum Cosmology · Physics 2025-07-14 Clifford M. Will

Quasi-equilibrium sequences of binary neutron stars are constructed for a variety of equations of state in general relativity. Einstein's constraint equations in the Isenberg-Wilson-Mathews approximation are solved together with the…

Solar and Stellar Astrophysics · Physics 2015-05-18 Keisuke Taniguchi , Masaru Shibata

Benefitting from the unequaled precision of the pulsar timing technique, binary pulsars are important testbeds of gravity theories, providing some of the tightest bounds on alternative theories of gravity. One class of well-motivated…

High Energy Astrophysical Phenomena · Physics 2022-05-13 Junjie Zhao , Paulo C. C. Freire , Michael Kramer , Lijing Shao , Norbert Wex

We study observational constraints on neutron star (NS) kicks for isolated pulsars and for neutron stars in binary systems. We are particularly interested in the evidence of kick-spin alignment/misalignment and its dependence on the neutron…

Astrophysics · Physics 2009-09-29 Chen Wang , Dong Lai , JinLin Han

[abridged] Chern-Simons (CS) modified gravity is a 4D effective theory that descends both from string theory and loop quantum gravity, and that corrects the Einstein-Hilbert action by adding the product of a scalar field and the…

General Relativity and Quantum Cosmology · Physics 2009-11-06 Carlos F. Sopuerta , Nicolas Yunes

We study quasi-equilibrium sequences of binary neutron stars in the framework of Damour-Esposito-Farese-type scalar-tensor theory of gravity with a massive scalar field, paying particular attention to the case where neutron stars are…

General Relativity and Quantum Cosmology · Physics 2023-09-06 Hao-Jui Kuan , Karim Van Aelst , Alan Tsz-Lok Lam , Masaru Shibata

Neutron stars exhibit magnetic fields and densities far beyond those achievable in terrestrial laboratories, offering a natural probe of strongly interacting matter under extreme conditions. Using observationally anchored mass-radius…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-13 Abriana Lyda , Prajwal MohanMurthy

In this paper, we present results obtained from our recent studies on the location of the innermost stable circular orbit (ISCO) for binary neutron stars (BNSs) in several levels of post Newtonian (PN) approximations. We reach the following…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Masaru Shibata , Keisuke Taniguchi , Takashi Nakamura

The low-energy limit of string theory contains an anomaly-canceling correction to the Einstein-Hilbert action, which defines an effective theory: Chern-Simons (CS) modified gravity. The CS correction consists of the product of a scalar…

General Relativity and Quantum Cosmology · Physics 2009-10-29 Nicolas Yunes , Frans Pretorius

We report on numerical results from an independent formalism to describe the quasi-equilibrium structure of nonsynchronous binary neutron stars in general relativity. This is an important independent test of controversial numerical…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Pedro Marronetti , Grant J. Mathews , James R. Wilson

Dynamical Chern-Simons gravity, a parity-violating modification of general relativity, is regarded as a low-energy effective theory arising from string theory. Gravitational waves provide a powerful probe for testing its predictions.…

General Relativity and Quantum Cosmology · Physics 2025-12-30 Xinyi Che , Xiangyu Lyu , Changfu Shi

Direct detections of gravitational waves offer a unique opportunity to test gravity in the highly dynamical and strong field regime. Current tests are typically performed assuming signals from quasicircular binaries. However, the complex…

General Relativity and Quantum Cosmology · Physics 2026-01-28 Soumen Roy , Justin Janquart

Eddington-inspired Born-Infeld gravity is an important modification of Einstein's general relativity, which can give rise to non-singular cosmologies at the classical level, and avoid the end-stage singularity in a gravitational collapse…

General Relativity and Quantum Cosmology · Physics 2022-01-12 Pritam Banerjee , Debojyoti Garain , Suvankar Paul , Rajibul Shaikh , Tapobrata Sarkar

Equilibria of binary neutron stars in close circular orbits are computed numerically in a waveless formulation: The full Einstein-relativistic-Euler system is solved on an initial hypersurface to obtain an asymptotically flat form of the…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Koji Uryu , Francois Limousin , John L. Friedman , Eric Gourgoulhon , Masaru Shibata