# Slim accretion disks: theory and observational consequences

## TL;DR

This paper reviews the development of slim accretion disk theory over 30 years, highlighting unresolved theoretical issues and the importance of observational data in advancing understanding of these models.

## Contribution

It summarizes the progress and remaining challenges in the theoretical modeling of slim accretion disks and emphasizes the need for further development and observational comparison.

## Key findings

- Increased observational data supports the applicability of slim disk models.
- Critical theoretical issues like disk stability and magnetic field roles remain unresolved.
- Further model development and data comparison are essential for progress.

## Abstract

Slim accretion disks idea emerged over 30 years ago as an answer to several unsolved problems. Since that time there was a tremendous increase in the amount of observational data where this model applies. However, many critical issues on the theoretical side remain unsolved, as they are inherently difficult. This is the issue of the disk stability under the radiation pressure, the role of the magnetic field in the energy transfer inside the disk and the formation (or not) of a warm corona, and outflows. Thus the progress has to be done both through further developments of the model and through the careful comparison to the observational data.