Testing the locality of transport in self-gravitating accretion discs. 2., The massive disc case
Articolo
Data di Pubblicazione:
2005
Citazione:
Testing the locality of transport in self-gravitating accretion discs. 2., The massive disc case / G. Lodato, W.K.M. Rice. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 358:4(2005), pp. 1489-1500. [10.1111/j.1365-2966.2005.08875.x]
Abstract:
In this paper, we extend our previous analysis (Paper I) of the transport properties induced by
gravitational instabilities in cooling, gaseous accretion discs to the case where the disc mass is
comparable to the central object. In order to do so, we have performed global, three-dimensional
smoothed particle hydrodynamics simulations of massive discs. These new simulations show
a much more complex temporal evolution with respect to the less massive case. Whereas
in the case of low disc mass a self-regulated, marginally stable state (characterized by an
approximately constant radial profile of the stability parameter Q) is easily established, in the
case of high disc mass we observe the development of an initial transient and subsequent settling
down in a self-regulated state in some simulations, or a series or recurrent spiral episodes,
with low azimuthal wavenumber m, in others. Accretion in this last case can therefore be a
highly variable process. On the other hand, we find that the secular evolution of the disc is
relatively slow. In fact, the time average of the stress induced by self-gravity results in accretion
time-scales much longer than the dynamical time-scale, in contrast with previous isothermal
simulations of massive accretion discs.We have also compared the resulting stress tensor with
the expectations based on a local theory of transport, finding no significant evidence for global
wave energy transport.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Accretion, accretion discs ; gravitation ; instabilities ; stars: formation ; galaxies:
active ; galaxies: spiral.
Elenco autori:
G. Lodato, W.K.M. Rice
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