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Rotating relativistic stars are receiving significant attention in recent years, because of the information they can yield about the equation of state of matter at extremely high densities and because they are one of the more possible…

General Relativity and Quantum Cosmology · Physics 2016-10-19 Nikolaos Stergioulas

The evolution of a neutron-star r-mode driven unstable by gravitational radiation (GR) is studied here using numerical solutions of the full non-linear fluid equations. The amplitude of the mode grows to order unity before strong shocks…

Astrophysics · Physics 2009-10-31 Lee Lindblom , Joel E. Tohline , Michele Vallisneri

We study the problem of detecting, and infering astrophysical information from, gravitational waves from a pulsating neutron star. We show that the fluid f and p-modes, as well as the gravitational-wave w-modes may be detectable from…

General Relativity and Quantum Cosmology · Physics 2009-10-31 K. D. Kokkotas , T. A. Apostolatos , N. Andersson

Non-radial oscillations of neutron stars provide a powerful probe of stellar structure and relativistic gravity, but a fully general relativistic treatment for gravitationally coupled two-fluid stars with independently conserved currents…

General Relativity and Quantum Cosmology · Physics 2026-05-06 Ankit Kumar , Daniel A. Caballero , Hajime Sotani , Nicolás Yunes

We study the r-modes and rotational ``hybrid'' modes of relativistic stars. As in Newtonian gravity, the spectrum of low-frequency rotational modes is highly sensitive to the stellar equation of state. If the star and its perturbations obey…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Keith H. Lockitch , Nils Andersson , John L. Friedman

In this paper we compute general-relativistic polytropic models simulating rigidly rotating, pulsating neutron stars. These relativistic compact objects, with a radius of $\sim 10 \, \mathrm{km}$ and mass between $\sim 1.4$ and $3.2$ solar…

General Relativity and Quantum Cosmology · Physics 2014-10-14 Vassilis Geroyannis , Eleftheria Tzelati

An approximate strategy for studying the evolution of binary systems of extended objects is introduced. The stars are assumed to be polytropic ellipsoids. The surfaces of constant density maintain their ellipsoidal shape during the time…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Dörte Hansen

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 present new results for pulsating stars in general relativity. First we show that the so-called gravitational-wave modes of a neutron star can be excited when a gravitational wave impinges on the star. Numerical simulations suggest that…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Nils Andersson , Kostas D. Kokkotas

We study the dynamical evolution of the gravitational-wave driven instability of the f-mode in rapidly rotating relativistic stars. With an approach based on linear perturbation theory we describe the evolution of the mode amplitude and…

Solar and Stellar Astrophysics · Physics 2015-06-11 A. Passamonti , E. Gaertig , K. D. Kokkotas. D. Doneva

It has been recently argued through numerical work that rotating stars with a high degree of differential rotation are dynamically unstable against bar-mode deformation, even for values of the ratio of rotational kinetic energy to…

Astrophysics · Physics 2009-06-23 Pablo Cerdá-Durán , Vicent Quilis , José A. Font

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 Rossby mode (r-mode) perturbations in pulsars as a steady gravitational wave (GW) sources have been explored. The time evolution and the intensity of the emitted GWs in terms of the strain tensor amplitude have been estimated with the…

Nuclear Theory · Physics 2023-05-01 Joydev Lahiri , D. N. Basu

Several classes of stars (most notably O and B main-sequence stars, as well as accreting white dwarfs and neutron stars) rotate quite rapidly, at spin frequencies greater than the typical g-mode frequencies. We discuss how rapid rotation…

Astrophysics · Physics 2009-10-30 Greg Ushomirsky , Lars Bildsten

We develop a general formalism to treat, in general relativity, the nonradial oscillations of a superfluid neutron star about static (non-rotating) configurations. The matter content of these stars can, as a first approximation, be…

General Relativity and Quantum Cosmology · Physics 2009-11-07 N. Andersson , G. L. Comer , D. Langlois

Neutron star asteroseismology offers a unique opportunity to probe nuclear physics through stellar oscillations. Although the pressure inside of a neutron star is typically assumed to be isotropic, pressure anisotropy can arise from various…

General Relativity and Quantum Cosmology · Physics 2026-01-13 Jihao Yu , Victor Guedes , Shu Yan Lau , Siddarth Ajith , Kent Yagi

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

Pulsar spin frequencies and their time evolution are an important source of information on compact stars and their internal composition. Oscillations of the star can reduce the rotational energy via the emission of gravitational waves. In…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Mark Alford , Simin Mahmoodifar , Kai Schwenzer

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

As gravitational wave instrumentation becomes more sensitive, it is interesting to speculate about subtle effects that could be analyzed using upcoming generations of detectors. One such effect that has great potential for revealing the…

High Energy Astrophysical Phenomena · Physics 2017-03-08 Cecilia Chirenti , Roman Gold , M. Coleman Miller