Cosmological evolution of supermassive black holes and AGN: a synthesis model for accretion and feedback

TL;DR

This paper develops a comprehensive model for the evolution of supermassive black holes and active galactic nuclei, integrating accretion, radiative, and kinetic feedback to better understand their growth and impact on cosmic structure.

Contribution

It introduces new constraints on SMBH evolution using a refined Soltan argument and links AGN downsizing to cosmological evolution of physical quantities.

Findings

Constraints on SMBH mass density at high redshift

Correlation between AGN downsizing and black hole growth

Evolutionary trends in AGN kinetic feedback

Abstract

The growth of supermassive black holes (SMBH) through accretion is accompanied by the release of enormous amounts of energy which can either be radiated away, as happens in quasars, advected into the black hole, or disposed of in kinetic form through powerful jets, as is observed, for example, in radio galaxies. Here, I will present new constraints on the evolution of the SMBH mass function and Eddington ratio distribution, obtained from a study of AGN luminosity functions aimed at accounting for both radiative and kinetic energy output of AGN in a systematic way. First, I discuss how a refined Soltan argument leads to joint constraints on the mass-weighted average spin of SMBH and of the total mass density of high redshift (z~5) and "wandering" black holes. Then, I will show how to describe the downsizing trend observed in the AGN population in terms of cosmological evolution of physical quantities (black hole mass, accretion rate, radiative and kinetic energy output). Finally, the redshift evolution of the AGN kinetic feedback will be briefly discussed and compared with the radiative output of the evolving SMBH population, thus providing a robust physical framework for phenomenological models of AGN feedback within structure formation.