  We consider a class of fully self-gravitating accretion disks, for which
efficient cooling mechanisms are assumed to maintain the disk close to the
margin of Jeans instability. For such self-regulated disks the equations become
very simple in the outer regions, where the angular momentum convective
transport approximately balances the viscous transport. These latter equations
are shown to lead naturally to a self-similar solution with flat rotation
curve, with circular velocity proportional to Mdot^(1/3) and essentially fixed
opening angle.
