Gravitational waves can be emitted by accretion discs if they undergo instabilities that generate a time varying mass quadrupole. In this work we investigate the gravitational signal generated by a thick accretion disc of 1 M⊙ around a static supermassive black hole of 106 M⊙, assumed to be formed after the tidal disruption of a solar type star. This torus has been shown to be unstable to a global non-axisymmetric hydrodynamic instability, the Papaloizou–Pringle instability, in the case where it is not already accreting and has a weak magnetic field. We start by deriving analytical estimates of the maximum amplitude of the gravitational wave signal, with the aim to establish its detectability by the Laser Interferometer Space Antenna (LISA). Then, we compare these estimates with those obtained through a numerical simulation of the torus, made with a 3D smoothed particle hydrodynamics code. Our numerical analysis shows that the measured strain is two orders of magnitude lower than the maximum value obtained analytically. However, accretion discs affected by the Papaloizou–Pringle instability may still be interesting sources for LISA, if we consider discs generated after deeply penetrating tidal disruptions of main-sequence stars of higher mass

Gravitational wave emission from unstable accretion discs in tidal disruption events / M. Toscani, G. Lodato, R. Nealon. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 489:1(2019 Oct), pp. 699-706. [10.1093/mnras/stz2201]

Gravitational wave emission from unstable accretion discs in tidal disruption events

M. Toscani
;
G. Lodato;
2019

Abstract

Gravitational waves can be emitted by accretion discs if they undergo instabilities that generate a time varying mass quadrupole. In this work we investigate the gravitational signal generated by a thick accretion disc of 1 M⊙ around a static supermassive black hole of 106 M⊙, assumed to be formed after the tidal disruption of a solar type star. This torus has been shown to be unstable to a global non-axisymmetric hydrodynamic instability, the Papaloizou–Pringle instability, in the case where it is not already accreting and has a weak magnetic field. We start by deriving analytical estimates of the maximum amplitude of the gravitational wave signal, with the aim to establish its detectability by the Laser Interferometer Space Antenna (LISA). Then, we compare these estimates with those obtained through a numerical simulation of the torus, made with a 3D smoothed particle hydrodynamics code. Our numerical analysis shows that the measured strain is two orders of magnitude lower than the maximum value obtained analytically. However, accretion discs affected by the Papaloizou–Pringle instability may still be interesting sources for LISA, if we consider discs generated after deeply penetrating tidal disruptions of main-sequence stars of higher mass
Settore FIS/05 - Astronomia e Astrofisica
   Dust and gas in planet forming discs (DUSTBUSTER)
   DUSTBUSTER
   EUROPEAN COMMISSION
   H2020
   823823
ott-2019
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/675701
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