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RESEARCH PRODUCT

Gravitational waves from oscillating accretion tori: Comparison between different approaches

José A. FontOlindo ZanottiAlessandro NagarAlessandro NagarRoberto De Pietri

subject

PhysicsNuclear and High Energy PhysicsAccretion (meteorology)Gravitational waveAstrophysics::High Energy Astrophysical PhenomenaAstrophysics (astro-ph)FOS: Physical sciencesGeneral Relativity and Quantum Cosmology (gr-qc)AstrophysicsGeneral Relativity and Quantum CosmologyCosmologyGravitationGeneral Relativity and Quantum CosmologyClassical mechanicsQuadrupole formulaQuasiperiodic functionQuantum electrodynamicsSchwarzschild metricPerturbation theory (quantum mechanics)

description

Quasi-periodic oscillations of high density thick accretion disks orbiting a Schwarzschild black hole have been recently addressed as interesting sources of gravitational waves. The aim of this paper is to compare the gravitational waveforms emitted from these sources when computed using (variations of) the standard quadrupole formula and gauge-invariant metric perturbation theory. To this goal we evolve representative disk models using an existing general relativistic hydrodynamics code which has been previously employed in investigations of such astrophysical systems. Two are the main results of this work: First, for stable and marginally stable disks, no excitation of the black hole quasi-normal modes is found. Secondly, we provide a simple, relativistic modification of the Newtonian quadrupole formula which, in certain regimes, yields excellent agreement with the perturbative approach. This holds true as long as back-scattering of GWs is negligible. Otherwise, any functional form of the quadrupole formula yields systematic errors of the order of 10%.

https://doi.org/10.1103/physrevd.72.024007