Algorithms and radiation dynamics for the vicinity of black holes I. Methods and codes

TL;DR

This paper develops methods and computational tools to analyze radiation effects on accretion disks around black holes, focusing on relativistic radiative transfer, particle trajectories, and observational predictions.

Contribution

It introduces new algorithms and codes for modeling radiation dynamics and particle motion in strong gravity near black holes, including methods to estimate black hole spin.

Findings

Successfully formulated and solved relativistic radiative transfer equations.

Developed codes for simulating particle trajectories and radiation forces.

Provided observational predictions for black hole systems.

Abstract

We examine radiation and its effects on accretion disks orbiting astrophysical black holes. These disks are thermally radiating and can be geometrically and optically thin or thick. In this first paper of the series, we discuss the physics and the formulation required for this study. Subsequently, we construct and solve the relativistic radiative transfer equation, or find suitable solutions where that is not possible. We continue by presenting some of the accretion disks we considered for this work. We then describe the families of codes developed in order to study particle trajectories in strong gravity, calculate radiation forces exerted onto the disk material, and generate observation pictures of black hole systems at infinity. Furthermore, we also examine the veracity and accuracy of our work. Finally, we investigate how we can further use our results to estimate the black hole spin and the motion of disk material subjected to these radiation forces.