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We study the radial pulsation frequencies of slowly rotating neutron stars in general relativistic formalism using realistic equations of state. It is found that the pulsation frequencies are always an increasing function of rotation rate.…

Astrophysics · Physics 2007-05-23 P. K. Sahu , A. R. Prasanna

Rotating relativistic stars have been studied extensively in recent years, both theoretically and observationally, because of the information they might yield about the equation of state of matter at extremely high densities and because…

High Energy Astrophysical Phenomena · Physics 2017-12-01 Vasileios Paschalidis , Nikolaos Stergioulas

The excitation of the axial quasi-normal modes of a relativistic star by scattered particles is studied by evolving the time dependent perturbation equations. This work is the first step towards the understanding of more complicated…

General Relativity and Quantum Cosmology · Physics 2009-10-31 V. Ferrari , K. D. Kokkotas

A binary neutron star merger produces a rapidly and differentially rotating compact remnant whose lifespan heavily affects the electromagnetic and gravitational emissions. Its stability depends on both the equation of state (EOS) and the…

General Relativity and Quantum Cosmology · Physics 2017-12-27 Gabriele Bozzola , Nikolaos Stergioulas , Andreas Bauswein

Gravitational waves are tiny disturbances in space-time and are a fundamental, although not yet directly confirmed, prediction of General Relativity. Rapidly rotating neutron stars are one of the possible sources of gravitational radiation…

Astrophysics · Physics 2008-12-03 Aaron Worley , Plamen G. Krastev , Bao-An Li

Using time evolutions of the relevant linearised equations we study non-axisymmetric oscillations of rapidly rotating and superfluid neutron stars. We consider perturbations of Newtonian axisymmetric background configurations and account…

Astrophysics · Physics 2009-11-13 Andrea Passamonti , Brynmor Haskell , Nils Andersson

In the era of gravitational wave astronomy, radial oscillations hold significant potential for not only uncovering the microphysics behind the internal structure but also investigating the stability of neutron stars (NSs). We start by…

Nuclear Theory · Physics 2026-02-02 Sayantan Ghosh , Sailesh Ranjan Mohanty , Tianqi Zhao , Bharat Kumar

This is a progress report on our study of the coupling of first-order radial and non-radial relativistic perturbations of a static spherical star. Our goal is to investigate the effects of this coupling on the gravitational wave signal of…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Andrea Passamonti , Marco Bruni , Leonardo Gualtieri , Carlos F. Sopuerta

Quasi-toroidal oscillations in slowly rotating stars are examined in the framework of general relativity. The oscillation frequency to first order of the rotation rate is not a single value even for uniform rotation unlike the Newtonian…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Yasufumi Kojima

In the modern era of abundant X-ray detections and the increasing momentum of gravitational waves astronomy, tests of General Relativity in strong field regime become increasingly feasible and their importance for probing gravity cannot be…

General Relativity and Quantum Cosmology · Physics 2020-09-25 Victor I. Danchev , Daniela D. Doneva , Stoytcho S. Yazadjiev

We compute spectra from accretion disks around rapidly rotating neutron stars. The full effect of general relativity is considered for the structure calculation of the stars. We take into account the Doppler shift, gravitational redshift…

Astrophysics · Physics 2007-05-23 Sudip Bhattacharyya , Dipankar Bhattacharya , Ranjeev Misra , Arun V. Thampan

We study the stability of neutron stars with toroidal magnetic fields by magnetohydrodynamic simulation in full general relativity under assumption of axial symmetry. Nonrotating and rigidly rotating neutron stars are prepared for a variety…

Astrophysics · Physics 2008-12-18 Kenta Kiuchi , Masaru Shibata , Shijun Yoshida

An understanding of the dynamics of differentially rotating systems is key to many areas of astrophysics. We investigate the oscillations of a simple system exhibiting differential rotation, and discuss issues concerning the role of…

Astrophysics · Physics 2009-01-09 Anna L. Watts , Nils Andersson , Horst Beyer , Bernard F. Schutz

Selfsimilarity relations for torsional oscillation frequencies of neutron star crust are discussed. For any neutron star model, the frequencies of fundamental torsional oscillations (with no nodes of radial wave function, i.e. at n=0, and…

Solar and Stellar Astrophysics · Physics 2023-01-13 D. G. Yakovlev

We study low-amplitude crustal oscillations of slowly rotating relativistic stars consisting of a central fluid core and an outer thin solid crust. We estimate the effect of rotation on the torsional toroidal modes and on the interfacial…

General Relativity and Quantum Cosmology · Physics 2009-11-13 M. Vavoulidis , K. D. Kokkotas , A. Stavridis

We consider the perturbations of a relativistic star as an initial-value problem. Having discussed the formulation of the problem (the perturbation equations and the appropriate boundary conditions at the centre and the surface of the star)…

General Relativity and Quantum Cosmology · Physics 2016-08-25 Gabrielle Allen , Nils Andersson , Kostas D. Kokkotas , Bernard F. Schutz

We study nonaxisymmetric perturbations of rotating relativistic stars. modeled as perfect-fluid equilibria. Instability to a mode with angular dependence $\exp(im\phi)$ sets in when the frequency of the mode vanishes. The locations of these…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Nikolaos Stergioulas , John L. Friedman

The radial oscillations of neutron stars are studied using equations of state derived from density-dependent relativistic mean-field (DDRMF) models, which effectively describe the ground-state properties of finite nuclei. A novel numerical…

Nuclear Theory · Physics 2025-08-19 Xuesong Geng , Kaixuan Huang , Hong Shen , Lei Li , Jinniu Hu

Rotating relativistic stars have been studied extensively in recent years, both theoretically and observationally, because of the information one could obtain about the equation of state of matter at extremely high densities and because…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Nikolaos Stergioulas

We study the stability against infinitesimal radial oscillations of neutron stars generated by a set of equations of state obtained from first-principle calculations in cold and dense QCD and constrained by observational data. We consider…

High Energy Physics - Phenomenology · Physics 2021-07-14 José C. Jiménez , Eduardo S. Fraga