# Astrophysical Black Holes: A Review

## TL;DR

This review traces the development of astrophysical black hole research, highlighting observational techniques, measurements of black hole properties, and their use in testing fundamental physics, from early discoveries to recent advancements.

## Contribution

It provides a comprehensive overview of the evolution of black hole studies, emphasizing recent methods for measuring black hole spins and their applications in fundamental physics.

## Key findings

- Development of techniques for measuring black hole spins
- Observation of black holes in systems like Cygnus X-1
- Use of black holes to test fundamental physics

## Abstract

In this review, I have tried to focus on the development of the field, from the first speculations to the current lines of research. According to Einstein's theory of general relativity, black holes are relatively simple objects and completely characterized by their mass, spin angular momentum, and electric charge, but the latter can be ignored in the case of astrophysical macroscopic objects. Search for black holes in the sky started in the early 1970s with the dynamical measurement of the mass of the compact object in Cygnus X-1. In the past 10-15 years, astronomers have developed some techniques for measuring the black hole spins. Recently, we have started using astrophysical black holes for testing fundamental physics.