New models and critical length scales for co-evolution between supermassive black holes and host galaxies

Most local galaxies host a central supermassive black hole. The existence of strong correlations between the host galaxy properties and their supermassive black hole’s mass suggests a close co-evolution. The scaling relations between black hole mass and bulge mass, luminosity, and stellar velocity dispersion have been extensively studied in the past. The co-evolution self-regulates both black hole growth and the star formation in host galaxy. The exact mechanisms that establish and maintain this co-evolution are still uncertain. Existing models are mostly based on the AGN wind/jet-driven feedback mechanisms. In this work, we propose a co-evolution model of black holes and host galaxy based on three major components: 1) the energy dissipation via black hole radiation; 2) the energy transfer by black hole luminosity to the surrounding gas; 3) the gravitational interaction with surrounding gas. Critical length scales in co-evolution were identified based on the interactions between three components. A new limit is also identified which is different from the standard Eddington limit. This work presents a new approach to understand the co-evolution of black holes and host galaxy. Sloan Digital Sky Survey Data Release 7 sample was used to explore the correlations and establish the co-evolution model.