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Related papers: Binary Neutron Stars in Quasi-equilibrium

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Two relations, the virial relation $M_{\rm ADM}=M_{\rm K}$ and the first law in the form $\delta M_{\rm ADM}=\Omega \delta J$, should be satisfied by a solution and a sequence of solutions describing binary compact objects in…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Masaru Shibata , Koji Uryu , John L. Friedman

Using an energy variational method, we calculate quasi-equilibrium configurations of binary neutron stars modeled as compressible triaxial ellipsoids obeying a polytropic equation of state. Our energy functional includes terms both for the…

Astrophysics · Physics 2009-10-30 James C. Lombardi , Frederic A. Rasio , Stuart L. Shapiro

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

A general relativistic version of the Euler equation for perfect fluid hydrodynamics is applied to a system of two neutron stars orbiting each other. In the quasi-equilibrium phase of the evolution of this system, a first integral of motion…

General Relativity and Quantum Cosmology · Physics 2009-10-30 S. Bonazzola , E. Gourgoulhon , J. -A. Marck

We present a code to construct initial data for binary neutron star systems in which the stars are rotating. Our code, based on a formalism developed by Tichy, allows for arbitrary rotation axes of the neutron stars and is able to achieve…

Neutron stars in binary orbit emit gravitational waves and spiral slowly together. During this inspiral, they are expected to have very little vorticity. It is in fact a good approximation to treat the system as having zero vorticity, i.e.,…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Saul A. Teukolsky

We present results of numerical computations of quasiequilibrium sequences of binary neutron stars with zero vorticity, in the general relativistic framework. The Einstein equations are solved under the assumption of a conformally flat…

General Relativity and Quantum Cosmology · Physics 2007-05-23 S. Bonazzola , E. Gourgoulhon , J. -A. Marck

Binary neutron star mergers are studied using nonlinear 3+1 numerical relativity simulations and the analytical effective-one-body (EOB) model. The EOB model predicts quasiuniversal relations between the mass-rescaled gravitational wave…

General Relativity and Quantum Cosmology · Physics 2015-04-15 Sebastiano Bernuzzi , Alessandro Nagar , Simone Balmelli , Tim Dietrich , Maximiliano Ujevic

We present calculations of quasiequilibrium sequences of irrotational binary neutron stars based on realistic equations of state (EOS) for the whole neutron star interior. Three realistic nuclear EOSs of various softness and based on…

Astrophysics · Physics 2009-01-30 M. Bejger , D. Gondek-Rosinska , E. Gourgoulhon , P. Haensel , K. Taniguchi , J. L. Zdunik

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

We present a new numerical method for the construction of quasiequilibrium models of black hole-neutron star binaries. We solve the constraint equations of general relativity, decomposed in the conformal thin-sandwich formalism, together…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Thomas W. Baumgarte , Monica L. Skoge , Stuart L. Shapiro

In general neutron stars in binaries are spinning. Due to the existence of millisecond pulsars we know that these spins can be substantial. We argue that spins with periods on the order a few dozen milliseconds could influence the late…

General Relativity and Quantum Cosmology · Physics 2011-08-11 Wolfgang Tichy

We investigate close binary neutron stars in quasiequilibrium states in a general relativistic framework. We assume conformal flatness for the spatial metric and irrotational velocity field for the neutron stars. We adopt the polytropic…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Koji Uryu , Masaru Shibata , Yoshiharu Eriguchi

We report work towards a relativistic formulation for modeling strongly magnetized neutron stars, rotating or in a close circular orbit around another neutron star or black hole, under the approximations of helical symmetry and ideal MHD.…

General Relativity and Quantum Cosmology · Physics 2011-11-08 Charalampos Markakis , Koji Uryu , Eric Gourgoulhon

Gravitational waves from binary neutron stars in quasiequilibrium circular orbits are computed using an approximate method which we propose in this paper. In the first step of this method, we prepare general relativistic irrotational binary…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Masaru Shibata , Koji Uryu

Simulations of binary neutron stars have seen great advances in terms of physical detail and numerical quality. However, the spin of the neutron stars, one of the simplest global parameters of binaries, remains mostly unstudied. We present…

General Relativity and Quantum Cosmology · Physics 2015-04-15 Sebastiano Bernuzzi , Tim Dietrich , Wolfgang Tichy , Bernd Bruegmann

A new method is described for constructing initial data for a binary neutron-star (BNS) system in quasi-equilibrium circular orbit. Two formulations for non-conformally flat data, waveless (WL) and near-zone helically symmetric (NHS), are…

General Relativity and Quantum Cosmology · Physics 2013-05-29 Koji Uryu , Francois Limousin , John L. Friedman , Eric Gourgoulhon , Masaru Shibata

Information about the last stages of a binary neutron star inspiral and the final merger can be extracted from quasi-equilibrium configurations and dynamical evolutions. In this article, we construct quasi-equilibrium configurations for…

We present new sequences of general relativistic, quasiequilibrium black hole-neutron star binaries. We solve for the gravitational field in the conformal thin-sandwich decomposition of Einstein's field equations, coupled to the equations…

Astrophysics · Physics 2009-11-11 Keisuke Taniguchi , Thomas W. Baumgarte , Joshua A. Faber , Stuart L. Shapiro

Determining the equation of state of matter at nuclear density and hence the structure of neutron stars has been a riddle for decades. We show how the imminent detection of gravitational waves from merging neutron star binaries can be used…

General Relativity and Quantum Cosmology · Physics 2014-09-05 Kentaro Takami , Luciano Rezzolla , Luca Baiotti