2004/03/08 by G. Lodato, W. K. M. Rice · 3 citations
Physics and Astronomy · #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2004.07811.x
published as Mon.Not.Roy.Astron.Soc. 351 (2004) 630 · 15 pages, 10 figures, accepted by MNRAS
arxiv created 2004/03/08 · arxiv updated 2009/12/01
In this paper we examine the issue of characterising the transport associated with gravitational instabilities in relatively cold discs, discussing in particular the conditions under which it can be described within a local, viscous framework. We present the results of global, three-dimensional, SPH simulations of self-gravitating accretion discs, in which the disc is cooled using a simple parametrisation for the cooling function. Our simulations show that the disc settles in a ``self-regulated'' state, where the axisymmetric stability parameter Q≈ 1 and where transport and energy dissipation are dominated by self-gravity. We have computed the gravitational stress tensor and compared our results with expectations based on a local theory of transport. We find that, as long as the disc mass is smaller than 0.25M⋆ and the aspect ratio H/R\lesssim 0.1, transport is determined locally, thus allowing for a viscous treatment of the disc evolution.