Title:	Slow m= 1 instabilities of softened gravity Keplerian discs
Authors:	Sridhar, S. Saini, T.D.
Keywords:	instabilities galaxies: nuclei celestial mechanics stellar dynamics
Issue Date:	May-2010
Publisher:	Wiley-Blackwell
Citation:	Monthly Notices of the Royal Astronomical Society, 2010, Vol.404, p527
Abstract:	We present the simplest model that permits a largely analytical exploration of the m= 1 counter-rotating instability in a 'hot' nearly Keplerian disc of collisionless self-gravitating matter. The model consists of a two-component softened gravity disc, whose linear modes are analysed using the Wentzel–Kramers–Brillouin approximation. The modes are slow in the sense that their (complex) frequency is smaller than the Keplerian orbital frequency by a factor which is of order the ratio of the disc mass to the mass of the central object. Very simple analytical expressions are derived for the precession frequencies and growth rates of local modes; it is shown that a nearly Keplerian disc must be unrealistically hot to avoid an overstability. Global modes are constructed for the case of zero net rotation.
Description:	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
URI:	http://hdl.handle.net/2289/3986
ISSN:	1365-2966 (Online) 0035-8711
Alternative Location:	http://adsabs.harvard.edu/abs/2010MNRAS.404..527S http://arxiv.org/abs/0911.2183 http://dx.doi.org/10.1111/j.1365-2966.2010.16306.x
Copyright:	2010 Authors and the Royal Astronomical Society
Appears in Collections:	Research Papers (A&A)

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