Mergers and binary systems of SMBH in the contexts of nuclear activity and galaxy evolution

TL;DR

This paper explores how the evolution of binary supermassive black holes influences active galactic nuclei and galaxy development, proposing a four-stage model that explains diverse AGN properties and behaviors.

Contribution

It introduces a four-stage evolutionary framework for binary SMBHs that links their dynamics to various observed AGN phenomena and galaxy evolution processes.

Findings

Binary SMBH evolution correlates with AGN activity stages

The model explains variability and outflows in AGN

Different AGN classes correspond to specific SMBH merger stages

Abstract

The dynamic evolution of binary systems of supermassive black holes (SMBH) may be a key factor affecting a large fraction of the observed properties of active galactic nuclei (AGN) and galaxy evolution. Different classes of AGN can be related in general to four evolutionary stages in a binary SMBH: 1) early merger stage; 2) wide pair stage; 3) close pair stage; and 4) pre-coalescence stage. This scheme can explain a variety of properties of AGN: radio and optical luminosity differences between different classes of AGN, long-term and short-term variability, quasi-periodic nuclear flares, recurrent formation of relativistic outflows in AGN and their apparent morphology and kinematics.