Peculiar black hole accretion rates in AGN with highest star formation rates in the universe

TL;DR

This paper investigates the peculiar black hole accretion behaviors in high star formation rate AGN, proposing that powerful jets initially enhance star formation before shifting to suppress it, revealing a transitional feedback mechanism.

Contribution

It introduces a new model linking AGN jet activity to a transition from high to low accretion rates, explaining observed high-redshift galaxy behaviors.

Findings

AGN with high star formation rates show a transition from near-Eddington to advection-dominated accretion.

Powerful FRII jets initially enhance star formation before suppressing it.

High-redshift AGN data align with predictions connecting to low-redshift radio AGN behavior.

Abstract

Pouliasis et al (2022b) explored star formation rates, black hole accretion rates, and stellar mass of active galaxies at redshift above 3.5, uncovering a leveling off of the star formation rate at high stellar mass, which they consider to be evidence of AGN feedback. Their data shows that as AGN approach the flattening of the curve in the star formation rate - stellar mass plane, the accretion rates begin to drop. We describe the nature of the AGN feedback responsible for this in terms of powerful FRII jets enhancing star formation rates but eventually also triggering a shift in accretion from near-Eddington rates to advection dominated. These systems are on the cusp of a dramatic transition where the active galaxy goes from strong enhancement to large suppression of star formation in a way that produces the steeper slope for radio AGN at low redshift compared to radio AGN at higher redshift and to jetless AGN. We argue, therefore, that the data of Pouliasis et al constitute the high redshift objects predicted by Singh et al (2021) that connect to the low redshift behavior of radio AGN shown in Comerford et al (2020).