Relativistic slim disks with vertical structure

TL;DR

This paper develops a detailed relativistic model of slim accretion disks incorporating vertical energy transport, providing insights into their structure and spectra, especially at high accretion rates and alpha parameters.

Contribution

It introduces a two-dimensional relativistic slim disk model with vertical structure and radiative transfer, advancing beyond previous height-averaged models.

Findings

Surface density and velocity differ by 20-30% from previous models.

Emission profiles and spectra are similar to polytropic models.

Effective optical depth drops below unity at high alpha and accretion rates.

Abstract

We report on a scheme for incorporating vertical radiative energy transport into a fully relativistic, Kerr-metric model of optically thick, advective, transonic alpha disks. Our code couples the radial and vertical equations of the accretion disk. The flux was computed in the diffusion approximation, and convection is included in the mixing-length approximation. We present the detailed structure of this "two-dimensional" slim-disk model for alpha=0.01. We then calculated the emergent spectra integrated over the disk surface. The values of surface density, radial velocity, and the photospheric height for these models differ by 20%-30% from those obtained in the polytropic, height-averaged slim disk model considered previously. However, the emission profiles and the resulting spectra are quite similar for both types of models. The effective optical depth of the slim disk becomes lower than unity for high values of the alpha parameter and for high accretion rates.