Kavli Affiliate: Roberto Maiolino
| First 5 Authors: Alessandro Trinca, Rosa Valiante, Raffaella Schneider, Ignas Juodžbalis, Roberto Maiolino
| Summary:
Early JWST observations are providing growing evidence for a ubiquitous
population of accreting supermassive black holes (BHs) at high redshift, many
of which appear overmassive compared to the empirically-derived local scaling
relation between black hole mass and host galaxy stellar mass. In this study,
we leverage predictions from the semi-analytical Cosmic Archaeology Tool (CAT)
to reconstruct the evolutionary pathways for this overmassive BH population,
investigating how they assemble over cosmic time and interact with their host
galaxies. We find that the large $M_{rm BH}-M_{rm star}$ ratios can be
explained if light and heavy BH seeds grow by short, repeated episodes of
super-Eddington accretion, triggered by major galaxy mergers. On average, we
find that BH-galaxy co-evolution starts in earnest only at $z < 8$, when
$simeq 30%$ of the final galaxy stellar mass has formed outside the massive
black hole host. Our model suggests that super-Eddington bursts of accretion
last between $0.5-3$ Myr, resulting in a duty cycle of $1-4 %$ for the target
BH sample. The boost in luminosity of BHs undergoing super-Eddington accretion
helps explaining the luminosity function of Active Galactic Nuclei observed by
JWST. At the same time, a large population of these overmassive BHs are
predicted to be inactive, with Eddington ratio $lambda_{rm Edd} < 0.05$, in
agreement with recent observations.
| Search Query: ArXiv Query: search_query=au:”Roberto Maiolino”&id_list=&start=0&max_results=3