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Related papers: Simulating bulk viscosity in neutron stars. I. For…

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We present a systematic numerical relativity study of the impact of different treatment of microphysics and grid resolution in binary neutron star mergers. We consider series of simulations at multiple resolutions comparing hydrodynamics,…

High Energy Astrophysical Phenomena · Physics 2023-01-18 Francesco Zappa , Sebastiano Bernuzzi , David Radice , Albino Perego

The merger of two neutron stars has been proposed as a source of gamma-ray bursts, r-process elements, and detectable gravitational waves. Extracting information from observations of these phenomena requires fully relativistic simulations.…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Walter Landry , Saul A. Teukolsky

Observations of massive ($M \approx 2.0~M_\odot$) neutron stars (NSs), PSRs J1614-2230 and J0348+0432, rule out most of the models of nucleon-hyperon matter employed in NS simulations. Here we construct three possible models of…

High Energy Astrophysical Phenomena · Physics 2014-03-05 M. E. Gusakov , P. Haensel , E. M. Kantor

We study viscosity of the neutron star matter and $r$-mode instability in rotating neutron stars. Contributions to the shear and bulk viscosities from various processes are calculated with account of in-medium modifications of the…

Nuclear Theory · Physics 2015-06-23 E. E. Kolomeitsev , D. N. Voskresensky

We integrate for the first time the hydrodynamic Hall-Vinen-Bekarevich-Khalatnikov equations of motion of a $^{1}S_{0}$-paired neutron superfluid in a rotating spherical shell, using a pseudospectral collocation algorithm coupled with a…

Astrophysics · Physics 2009-11-13 C. Peralta , A. Melatos , M. Giacobello , A. Ooi

Which of the multiple models of causal and stable relativistic viscous fluids that have been developed is best suited to describe neutron stars? The modeling of out-of-equilibrium effects in these relativistic, astrophysical objects must be…

General Relativity and Quantum Cosmology · Physics 2025-09-19 Daniel A. Caballero , Nicolás Yunes

The full causal M\"uller-Israel-Stewart (MIS) theory of dissipative processes in relativistic fluids is applied to a flat, homogeneous and isotropic universe with bulk viscosity. It is clarified in which sense the so called truncated…

Astrophysics · Physics 2008-11-26 Winfried Zimdahl

We discuss the effect of nonlinear bulk viscosity and the associated reheating on the evolution of newly born, rapidly rotating neutron stars with r-modes destabilized through the Chandrasekhar-Friedman-Schutz (CFS) mechanism. Bulk…

Astrophysics · Physics 2007-05-23 Andreas Reisenegger , Axel Bonacic

The formulation of a universal theory for bulk viscosity and heat conduction represents a theoretical challenge for our understanding of relativistic fluid dynamics. Recently, it has been shown that the multifluid variational approach…

General Relativity and Quantum Cosmology · Physics 2020-10-15 Lorenzo Gavassino , Marco Antonelli , Brynmor Haskell

We study the effects of an elastic crust on the oscillation spectrum of superfluid neutron stars. Within the two fluid formalism, we consider Newtonian stellar models that include the relevant constituents of a mature neutron stars. The…

Solar and Stellar Astrophysics · Physics 2015-05-28 A. Passamonti , N. Andersson

Neutrino transport in spherically symmetric models of stellar core collapse and bounce has achieved a technically complete level, rewarded by the agreement among independent groups that a multi-dimensional treatment of the…

Astrophysics · Physics 2008-11-26 M. Liebendoerfer , U. -L. Pen , C. Thompson

We present a general formalism to treat slowly rotating general relativistic superfluid neutron stars. As a first approximation, their matter content can be described in terms of a two-fluid model, where one fluid is the neutron superfluid,…

General Relativity and Quantum Cosmology · Physics 2009-10-31 N. Andersson , G. L. Comer

We investigate the compressional modes of cold neutron stars with cores consisting of superfluid neutrons, superconducting protons and normal fluid electrons and muons, and crusts that contain superfluid neutrons plus a normal fluid of…

High Energy Astrophysical Phenomena · Physics 2018-10-15 P. B. Rau , I. Wasserman

We present our first successful numerical results of 3D general relativistic simulations in which the Einstein equation as well as the hydrodynamic equations are fully solved. This paper is especially devoted to simulations of test problems…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Masaru Shibata

The contribution from hyperons to the bulk viscosity of neutron star matter is calculated. Compared to previous works we use for the weak interaction the one-pion exchange model rather than a current-current interaction, and include the…

Nuclear Theory · Physics 2009-11-10 E. N. E. van Dalen , A. E. L. Dieperink

We consider static neutron stars within the framework of $R^2$ gravity. The neutron fluid is described by three different types of realistic equations of state (soft, moderately stiff, and stiff). Using the observational data on the neutron…

General Relativity and Quantum Cosmology · Physics 2018-06-08 Vladimir Folomeev

We construct new equations of state for baryons at sub-nuclear densities for the use in core-collapse simulations of massive stars. The abundance of various nuclei is obtained together with thermodynamic quantities. A model free energy is…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Shun Furusawa , Kohsuke Sumiyoshi , Shoichi Yamada , Hideyuki Suzuki

The dynamics of a neutron star after a glitch involve the transfer of angular momentum from the crust (where the glitch is presumed to originate) to the liquid core, causing the core to spin up. The crust-core coupling, which determines how…

High Energy Astrophysical Phenomena · Physics 2024-10-21 J. R. Fuentes , Vanessa Graber

We consider cosmological scenarios originating from a single imperfect fluid with bulk viscosity and apply Eckart's and both the full and the truncated M\"uller-Israel-Stewart's theories as descriptions of the non-equilibrium processes. Our…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-12 Oliver F. Piattella , Júlio C. Fabris , Winfried Zimdahl

We analyze damping of oscillations of general relativistic superfluid neutron stars. To this aim we extend the method of decoupling of superfluid and normal oscillation modes first suggested in [Gusakov & Kantor PRD 83, 081304(R) (2011)].…

Solar and Stellar Astrophysics · Physics 2013-05-21 M. E. Gusakov , E. M. Kantor , A. I. Chugunov , L. Gualtieri