Super-Eddington black hole accretion: Polish doughnuts and slim disks

TL;DR

This paper reviews the development of models for super-Eddington black hole accretion, focusing on Polish doughnuts and slim disks, highlighting their structures, radiation properties, and differences in accretion rates.

Contribution

It compares and clarifies the physical characteristics and observational implications of Polish doughnuts and slim disks in super-Eddington accretion regimes.

Findings

Polish doughnuts are thick, optically thick tori with funnels that collimated radiation.

Slim disks have moderate super-Eddington rates with more disk-like shapes.

Both models explain high luminosities and spectral features of super-Eddington accretion.

Abstract

The theory of highly super-Eddington black hole accretion was developed in the 1980s in Warsaw by Paczynski and his collaborators in terms of "Polish doughnuts", i.e. low viscosity, rotating accretion flows that are optically thick, radiation pressure supported, cooled by advection, and radiatively very inefficient. Polish doughnuts resemble fat tori with two narrow funnels along rotation axis. The funnels collimate radiation into beams with highly super-Eddington luminosities. "Slim disks" introduced later by Abramowicz, Lasota and collaborators, have only moderately super-Eddington accretion rates, rather disk-like shapes, and almost thermal spectra.