The broad Fe K{\alpha} line and supermassive black holes

TL;DR

This paper reviews observational and theoretical studies of the broad Fe Kα spectral line, emphasizing its significance in understanding supermassive black holes, their environments, and testing General Relativity.

Contribution

It provides a comprehensive overview of recent advances in using the broad Fe Kα line to study black hole properties and relativistic effects.

Findings

Broad Fe Kα line helps determine black hole masses and spins.

It probes space-time geometry near black holes.

It tests predictions of General Relativity in strong gravity regimes.

Abstract

Here we present an overview of some of the most significant observational and theoretical studies of the broad Fe K{\alpha} spectral line, which is believed to originate from the innermost regions of relativistic accretion disks around central supermassive black holes of galaxies. The most important results of our investigations in this field are also listed. All these investigations indicate that the broad Fe K{\alpha} line is a powerful tool for studying the properties of the supermassive black holes (such as their masses and spins), space-time geometry (metric) in their vicinity, their accretion physics, probing the effects of their strong gravitational fields, and for testing the certain predictions of General Relativity.