Semi-analytical modeling reveals episodic super-Eddington accretion driving early black hole growth in high-redshift galaxies, explaining overmassive mass ratios observed by JWST.
Key Points
To determine how high-redshift overmassive black holes assemble over cosmic time and establish elevated black hole-to-host galaxy mass ratios.
Simulated black hole evolutionary pathways across cosmic time using the semi-analytical Cosmic Archaeology Tool (CAT).
Modeled accretion histories from light and heavy black hole seeds, incorporating merger-triggered accretion episodes and tracking galaxy stellar mass growth.
Short, repeated bursts of super-Eddington accretion lasting 0.5 to 3 Myr (with a duty cycle of 1% to 4%) successfully account for the elevated black hole-to-stellar mass ratios.
Black hole-galaxy co-evolution begins primarily at redshift z < 8, when approximately 30% of the final galaxy stellar mass forms outside the primary host.
The simulated accretion bursts reproduce JWST Active Galactic Nuclei luminosity functions while predicting a large inactive population with Eddington ratios λEdd < 0.05.