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Perturbations of rotating relativistic stars can be classified by their behavior under parity. For axial perturbations (r-modes), initial data with negative canonical energy is found with angular dependence $e^{im\phi}$ for all values of…

General Relativity and Quantum Cosmology · Physics 2009-10-30 John L. Friedman , Sharon M. Morsink

I study the effect of nuclear equation of state on the r-mode instability of a rotating neutron star. I consider the case where the crust of the neutron star is perfectly rigid and I employ the related theory introduced by Lindblom {\it et…

Nuclear Theory · Physics 2015-03-18 Ch. C. Moustakidis

We study the long time behavior of isentropic compressible Euler equations with linear damping driven by a white-in-time noise, on a one-dimensional torus. We prove the existence of a statistically stationary solution in the class of weak…

Analysis of PDEs · Mathematics 2025-11-03 Jeffrey Kuan , Krutika Tawri , Konstantina Trivisa

In the recent paper, the global-in-time inviscid limit of the three-dimensional (3D) isentropic compressible Navier-Stokes equations is considered. First, when viscosity coefficients are given as a constant multiple of density's power…

Analysis of PDEs · Mathematics 2019-11-21 Yongcai Geng , Yachun Li , Shengguo Zhu

Viscosity driven bar mode secular instabilities of rapidly rotating neutron stars are studied using LORENE/Nrotstar code. These instabilities set a more rigorous limit to the rotation frequency of neutron star than the Kepler frequency/mass…

High Energy Astrophysical Phenomena · Physics 2018-04-30 Arkadip Basak

We apply the post-quasi--static approximation, an iterative method for the evolution of self-gravitating spheres of matter, to study the evolution of anisotropic non-adiabatic radiating and dissipative distributions in General Relativity.…

General Relativity and Quantum Cosmology · Physics 2010-05-25 C. Peralta , L. Rosales , B. Rodrí guez-Mueller , W. Barreto

Normal stresses in sheared suspensions of non-Brownian particles are obtained from numerical simulations in the viscous regime. The stresses are determined in homogeneous shear of non-buoyant particles and by analyzing shear-induced…

Soft Condensed Matter · Physics 2024-10-02 William Chèvremont , Bruno Chareyre , Hugues Bodiguel

The only r-modes that exist in a globally barotropic, rotating, Newtonian star are the fundamental $l = |m|$ solutions, where $l$ and $m$ are the indices of the spherical harmonic $Y_l^m$ that describe the mode's angular dependence. This is…

General Relativity and Quantum Cosmology · Physics 2023-05-23 Fabian Gittins , Nils Andersson

Despite more and more observational data, stellar acoustic oscillation modes are not well understood as soon as rotation cannot be treated perturbatively. In a way similar to semiclassical theory in quantum physics, we use acoustic ray…

Solar and Stellar Astrophysics · Physics 2011-09-16 M. Pasek , B. Georgeot , F. Lignieres , D. R. Reese

In this work, we perform the first systematic investigation of effects of the presence of dark matter on $r$-mode oscillations in neutron stars (NSs). Using a self-interacting dark matter (DM) model based on the neutron decay anomaly and a…

High Energy Astrophysical Phenomena · Physics 2023-12-15 Swarnim Shirke , Suprovo Ghosh , Debarati Chatterjee , Laura Sagunski , Jürgen Schaffner-Bielich

A new type of systematic approach to study the incompressible Euler equations numerically via the vanishing viscosity limit is proposed in this work. We show the new strategy is unconditionally stable that the $L^2$-energy dissipates and…

Numerical Analysis · Mathematics 2024-06-19 Xinyu Cheng , Zhaonan Luo , Sheng Wang

Dissipative processes acting in rotating neutron stars are essential in preventing the growth of the r-mode instability. We estimate the damping time of r-modes of an hypothetical compact quark star made up by color flavor locked quark…

High Energy Physics - Phenomenology · Physics 2009-01-09 Massimo Mannarelli , Cristina Manuel , Basil A. Sa'd

The relativistic Cowling approximation, where the metric perturbations are neglected during the fluid oscillations, is often adopted for considering the gravitational waves from the protoneutron stars (PNSs) provided via core-collapse…

High Energy Astrophysical Phenomena · Physics 2020-10-07 Hajime Sotani , Tomoya Takiwaki

In this paper we show how quantum corrections, although perturbatively small, may play an important role in the analysis of the existence of some classical models. This, in fact, appears to be the case of static, uniform--density models of…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Manuela Campanelli , Carlos O. Lousto

We present a new hydro code based on spectral methods using spherical coordinates. The first version of this code aims at studying time evolution of inertial modes in slowly rotating neutron stars. In this article, we introduce the…

General Relativity and Quantum Cosmology · Physics 2009-11-07 L. Villain , S. Bonazzola

We present some results about a novel damping mechanism of r-mode oscillations in neutron stars due to processes that change the number of protons, neutrons and electrons. Deviations from equilibrium of the number densities of the various…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Massimo Mannarelli , Giuseppe Colucci , Cristina Manuel

We present a new survey of the radial oscillation modes of neutron stars. This study complements and corrects earlier studies of radial oscillations. We present an extensive list of frequencies for the most common equations of state and…

General Relativity and Quantum Cosmology · Physics 2011-05-23 Kostas. D. Kokkotas , Johannes Ruoff

We consider the zero viscosity limit of long time averages of solutions of damped and driven Navier-Stokes equations in ${\mathbb R}^2$. We prove that the rate of dissipation of enstrophy vanishes. Stationary statistical solutions of the…

Analysis of PDEs · Mathematics 2009-11-11 P. Constantin , F. Ramos

We investigate the impact of the neutron-star matter equation of state on the $f$- and $p_1$-mode oscillations of neutron stars obtained within the Cowling approximation and linearized general relativity. The $f$- and $p_1$-mode oscillation…

Nuclear Theory · Physics 2022-10-10 Athul Kunjipurayil , Tianqi Zhao , Bharat Kumar , Bijay K. Agrawal , Madappa Prakash

We consider several models of nonlinear wave equations subject to very strong damping and quasi-periodic external forcing. This is a singular perturbation, since the damping is not the highest order term. We study the existence of response…

Analysis of PDEs · Mathematics 2015-01-27 Renato C. Calleja , Alessandra Celletti , Livia Corsi , Rafael de la Llave