  We consider a class of steady-state self-gravitating accretion disks for
which efficient cooling mechanisms are assumed to operate so that the disk is
self-regulated at a condition of approximate marginal Jeans stability. In an
earlier paper, this scenario had been shown to lead naturally, in the absence
of a central point mass, to a self-similar solution characterized by a flat
rotation curve. In this article we investigate the entire parameter space
available for such self-regulated accretion disks and provide two non-trivial
extensions of the model. The first extension is that of a bimodal disk,
obtained by partially relaxing the self-regulation constraint, so that full
matching with an inner "standard" Keplerian accretion disk takes place. The
second extension is the construction of self-regulated accretion disks embedded
in a diffuse spherical "halo". The analysis is further strengthened by a
careful discussion of the vertical structure of the disk, in such a way that
the transition from self-gravity dominated to non-gravitating disks is covered
uniformly.
