The Growth of High-Redshift Central Black Holes and their Hosts

by Olmo Piana (National Taiwan Normal University a Taipei)

Friday 8 Sept 2023, 11:30 → 12:30 Europe/Rome

Sala Jappelli (Osservatorio Astronomico di Padova)

The fast-growing observational sample of high-redshift supermassive black holes in the past years has raised multiple questions about their early accretion rates and duty cycles. At the same time, the observed correlations between these black holes and the physical properties of the host galaxies make us wonder about how the gas thermodynamical evolution is linked to their growth. Most cosmological numerical simulations and semi-analytic models are able to reproduce the available high-z observables (such as the black hole and stellar mass function and the quasar and galaxy UV luminosity functions at z~5-7) despite implementing different models of early (z>10) black hole growth and feedback. We refine the galactic gas thermodynamical evolution and the black hole accretion and feedback mechanisms in our model (DELPHI) with the aim to break this degeneracy, showing how different black hole growth models impact quasar and galaxy observables at z>5. Our main findings are that i) while Eddington-limited and super-Eddington accretion models are both consistent with observations at z<6, they become very clearly distinguishable at higher redshift, and ii) the super-Eddington accretion model scenario naturally yields a much lower number density of intermediate-mass black holes (with masses between 10^4-10^6 solar masses) at high redshift. Adding physically-motivated assumptions on the nature of black hole feedback we can also study the emergence of jetted AGN, focusing on their duty cycle across a wide halo mass range.

 

Link alla videochiamata: https://meet.google.com/gza-usif-mav
 

Oppure digita: ‪(IT) +39 02 3041 9858‬ PIN: ‪917 861 403‬#