Ongoing

Daniele Spinoso, Silvia Bonoli, David Izquierdo-Villalba, Markos Polkas et al.

The physical model which describes the mass-growth of SMBHs in L-Galaxies has been shown to require adaptation when applied to the Millennium-II merger trees (see Spinoso et al. 2023, project: Black Hole seeding). In particular, the total mass-growth of massive BHs (i.e. integrated across their whole cosmological evolution) is well-reproduced by the model presented in Izquierdo-Villalba et al 2020 (see project: Black holes). Nevertheless, when these prescriptions are applied to MR-II, massive BHs grow most of their mass at z>3, in contrast with current observations which place the peak of AGN activity at z~2, as inferred from the evolution of the AGN luminosity function (LF). This mismatch appears to be due to the strength of cold-gas inflows triggered by tidal interactions during galaxy mergers, and their prompt accretion onto the central MBHs of the merger-remnant galaxies. This project aims at exploring improvements to the model of gas-inflow onto central BHs, focusing in particular on delaying the growth of MBHs hosted in dwarf / Milky-Way halos (i.e. the mass regime well-sampled by the Millennium-II). This would allow to retain the good predictions of the Izquierdo-Villalba et al 2020 model regarding the integrated mass-growth of MBHs while recovering the agreement with currrent constraints on the evolution of AGN LF, at the same time.