Data di Pubblicazione:
2016
Citazione:
Lense–Thirring precession around supermassive black holes during tidal disruption events / A. Franchini, G. Lodato, S. Facchini. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 455:2(2016 Jan), pp. 1946-1956. [10.1093/mnras/stv2417]
Abstract:
A tidal disruption event occurs when a star wanders close enough to a black hole to be disrupted by its tidal force. The debris of a tidally disrupted star are expected to form an accretion disc around the supermassive black hole. The light curves of these events sometimes show a quasi-periodic modulation of the flux that can be associated with the precession of the accretion disc due to the Lense-Thirring (`frame-dragging') effect. Since the initial star orbit is in general inclined with respect to the black hole spin, this misalignment combined with the Lense-Thirring effect leads to a warp in the disc. In this paper, we provide a simple model of the system composed by a thick and narrow accretion disc surrounding a spinning supermassive black hole, with the aim to: (a) compute the expected precession period as a function of the system parameters, (b) discuss the conditions that have to be satisfied in order to have rigid precession, (c) investigate the alignment process, highlighting how different mechanisms play a role leading the disc and the black hole angular momenta into alignment.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
accretion, accretion discs; black hole physics; hydrodynamics; galaxies: nuclei
Elenco autori:
A. Franchini, G. Lodato, S. Facchini
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