G. Bjornsson — Page 2

arXiv1996

Accretion Disk Models with Self-Consistent Advective Cooling and Heating

We present solutions to the accretion disk structure equations in which advective cooling is accounted for in a self-consistent way. It is shown that for high rates of accretion, above a critical value, when without advection there are no solutions extending continuously from large to small radii, there exist global solutions with self-consistent advective cooling. These solutions are quite different fromthose solutions obtained earlier by other authors, where advective cooling was not treated self-consistently.

astro-ph↗

arXiv1995

Structure Of The Accretion Disks With Opticallt Thick-Thin Transitions

We present here the solution for accretion disk structure, which describes continuously the transition between optically thick and optically thin disk regions. We show that the disk structure equations without advection, used here, give two branches of solutions which do not intersect for $L<L_{b}\lesssim 0.6 L_{\rm Edd}$ for $α=1.0$ and $M_{BH}=10^8 M_\odot$. For larger luminosities there are no global solutions of the equations without advection. We suggest, as one of the possibilities, that advection becomes important even before, at luminosities $\sim0.1L_{\rm Edd}$, when the inner disk regions become unstable due to radiation pressure dominance and induce the transition from optically thick to optically thin disk in the global solution.

astro-ph↗