Massive Black Holes: Evidence, Demographics and Cosmic Evolution

TL;DR

This paper reviews observational evidence, demographics, and cosmic evolution of massive black holes, highlighting their role in galaxy formation and potential for testing gravitational theories near event horizons.

Contribution

It provides a comprehensive synthesis of current knowledge on black hole properties, distribution, and their evolution, and discusses future prospects for using black holes to test gravity theories.

Findings

Massive black holes are prevalent in galactic centers.

Black hole mass and spin distributions are characterized.

Black holes can serve as laboratories for testing gravity theories.

Abstract

The article summarizes the observational evidence for the existence of massive black holes, as well as the current knowledge about their abundance, their mass and spin distributions, and their cosmic evolution within and together with their galactic hosts. We finish with a discussion of how massive black holes may in the future serve as laboratories for testing the theory of gravitation in the extreme curvature regimes near the event horizon.