Slow pressure modes in thin accretion discs

Saini, Tarun Deep and Gulati, Mamta and Sridhar, S (2009) Slow pressure modes in thin accretion discs. In: Monthly Notices of the Royal Astronomical Society, 400 (4). pp. 2090-2097.

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Abstract

Thin accretion discs around massive compact objects can support slow pressure modes of oscillations in the linear regime that have azimuthal wavenumber m = 1. We consider finite, flat discs composed of barotropic fluid for various surface density profiles and demonstrate through WKB analysis and numerical solution of the eigenvalue problem - that these modes are stable and have spatial scales comparable to the size of the disc. We show that the eigenvalue equation can be mapped to a Schrodinger like equation. The analysis of this equation shows that all eigenmodes have discrete spectra. We find that all the models we have considered support negative frequency eigenmodes; however, the positive eigenfrequency modes are only present in power-law discs, albeit for physically uninteresting values of the power-law index beta and barotropic index gamma.

Item Type:	Journal Article
Additional Information:	copyright of this article belongs to John Wiley and Sons.
Keywords:	accretion;accretion discs;hydrodynamics;waves;methods: analytical.
Department/Centre:	Others
Date Deposited:	09 Jan 2010 09:44
Last Modified:	19 Sep 2010 05:53
URI:	http://eprints.iisc.ernet.in/id/eprint/25303

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