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Related papers: Relativistic r-modes and Shear viscosity: regulari…

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We derive the relativistic equations for stellar perturbations, including in a consistent way shear viscosity in the stress-energy tensor, and we numerically integrate our equations in the case of large viscosity. We consider the slow…

General Relativity and Quantum Cosmology · Physics 2010-11-11 L. Gualtieri , J. A. Pons , J. A. Miralles , V. Ferrari

The detectability of the gravitational-wave signal from $r$-modes depends on the interplay between the amplification of the mode by the CFS instability and its damping due to dissipative mechanisms present in the stellar matter. The…

High Energy Astrophysical Phenomena · Physics 2025-08-06 Kirill Y. Kraav , Mikhail E. Gusakov , Elena M. Kantor

In part I, we use the post-Newtonian (pn) order of Liouville's equation to study the normal modes of oscillation of a spherically symmetric relativistic system. Perturbations that are neutral in Newtonian approximation develop into a new…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Vahid Rezania

We consider both mode calculations and time evolutions of axial r-modes for relativistic uniformly rotating non-barotropic neutron stars, using the slow-rotation formalism, in which rotational corrections are considered up to linear order…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Johannes Ruoff , Kostas D. Kokkotas

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

The frequencies of r-mode oscillations of rotating neutron stars can be useful for guiding and interpreting gravitational wave and electromagnetic observations. The frequencies of slowly rotating, barotropic, and non-magnetic Newtonian…

General Relativity and Quantum Cosmology · Physics 2015-01-14 Ashikuzzaman Idrisy , Benjamin J. Owen , David I. Jones

We develop a numerical scheme for obtaining the $r$-mode oscillations of rapidly rotating relativistic stars. In the present scheme, we neglect all metric perturbations and only take account of the dynamics of the fluid in the background…

Astrophysics · Physics 2009-11-10 Shijun Yoshida , Shin'ichirou Yoshida , Yoshiharu Eriguchi

We study the viscous damping of r-modes of compact stars and analyze in detail the regions where small amplitude modes are unstable to the emission of gravitational radiation. We present general expressions for the viscous damping times for…

High Energy Astrophysical Phenomena · Physics 2015-03-17 Mark Alford , Simin Mahmoodifar , Kai Schwenzer

We use perturbation theory and the relativistic Cowling approximation to numerically compute characteristic oscillation modes of rapidly rotating relativistic stars which consist of a perfect fluid obeying a polytropic equation of state. We…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Stratos Boutloukos , Hans-Peter Nollert

An inconsistency between the theoretical analysis and numerical calculations of the relativistic $r$-modes puzzles the neutron star community since the Kojima's finding of the continuous part in the $r$-mode oscillation spectrum in 1997. In…

High Energy Astrophysical Phenomena · Physics 2022-11-16 Kirill Y. Kraav , Mikhail E. Gusakov , Elena M. Kantor

The axial modes for non-barotropic relativistic rotating neutron stars with uniform angular velocity are studied, using the slow-rotation formalism together with the low-frequency approximation, first investigated by Kojima. The time…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Johannes Ruoff , Kostas D. Kokkotas

The first results of numerical analysis of classical r-modes of {\it rapidly} rotating compressible stellar models are reported. The full set of linear perturbation equations of rotating stars in Newtonian gravity are numerically solved…

Astrophysics · Physics 2009-10-31 Shin'ichirou Yoshida , Shigeyuki Karino , Shijun Yoshida , Yoshiharu Eriguchi

We analyze the viscous damping of r-mode oscillations of compact stars, taking into account non-linear viscous effects in the large-amplitude regime. The qualitatively different cases of hadronic stars, strange quark stars, and hybrid stars…

High Energy Astrophysical Phenomena · Physics 2013-05-30 Mark G. Alford , Simin Mahmoodifar , Kai Schwenzer

The spectrum of radial oscillations of neutron stars is systematically studied within two frameworks of viscous relativistic hydrodynamics: the relativistic Navier-Stokes and Israel-Stewart theories. A correspondence is established between…

General Relativity and Quantum Cosmology · Physics 2026-01-09 Raissa F. P. Mendes , Amanda Guerrieri , João V. M. Muniz , Gabriel S. Rocha , Gabriel S. Denicol

In the present paper the axial quasi-normal modes of neutron stars in $f(R)$ gravity are examined using a large set of equations of state. The numerical calculations are made using two different approaches -- performing time evolution of…

General Relativity and Quantum Cosmology · Physics 2018-12-05 Jose Luis Blázquez-Salcedo , Daniela D. Doneva , Jutta Kunz , Kalin V. Staykov , Stoytcho S. Yazadjiev

We investigate shear and interface modes excited in neutron stars with an elastic crust in the full general relativistic framework and compare them to the results obtained within the relativistic Cowling approximation. We observe that the…

General Relativity and Quantum Cosmology · Physics 2025-03-19 C. J. Krüger , H. Sotani

Recent work has raised the exciting possibility that r-modes (Rossby waves) in rotating neutron star cores might be strong gravitational wave sources. We estimate the effect of a solid crust on their viscous damping rate and show that the…

Astrophysics · Physics 2009-10-31 Lars Bildsten , Greg Ushomirsky

We present an analytic description of the $r$-mode instability in newly-born neutron stars, using the approximation of uniform density. Our computation is consistently accurate to second order in the angular velocity of the star. We obtain…

Astrophysics · Physics 2011-05-23 K. D. Kokkotas , N. Stergioulas

We present an asymptotic theory that describes regular frequency spacings of pressure modes in rapidly rotating stars. We use an asymptotic method based on an approximate solution of the pressure wave equation constructed from a stable…

Solar and Stellar Astrophysics · Physics 2012-09-27 Michael Pasek , François Lignières , Bertrand Georgeot , Daniel R. Reese

We study oscillations of slowly rotating relativistic barotropic as well as non-barotropic polytropic stars in the Cowling approximation, including first order rotational corrections. By taking into account the coupling between the polar…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Johannes Ruoff , Adamantios Stavridis , Kostas D. Kokkotas
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