Title:	Slow pressure modes in thin accretion discs
Authors:	Saini, T.D. Gulati, Mamta Sridhar, S.
Keywords:	accretion discs hydrodynamics waves methods analytical
Issue Date:	15-Jan-2009
Publisher:	Wiley Interscience for the RAS
Citation:	Monthly Notices of the Royal Astronomical Society, 2009, Vol.400, p2090
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 Schrödinger-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 β and barotropic index γ.
Description:	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
URI:	http://hdl.handle.net/2289/3932
ISSN:	1365-2966 (Online) 0035-8711
Alternative Location:	http://adsabs.harvard.edu/abs/2009arXiv0901.4229D http://arxiv.org/abs/0901.4229 http://dx.doi.org/10.1111/j.1365-2966.2009.15602.x
Copyright:	2009 Wiley Interscience for the RAS
Appears in Collections:	Research Papers (A&A)

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