Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The locality of transport in self-gravitating accretion discs   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 $Q\approx 1$ 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 $0.25M_{\star}$ and the
aspect ratio $H/R\lesssim 0.1$, transport is determined locally, thus allowing
for a viscous treatment of the disc evolution.

11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph