Coffee talks
Friday 05/12/2025 @ 11:30, Sala riunioni quarto piano e on-line (meet.google.com/sue-bwvk-axf)
Francesco Shankar (University of Southampton), "Quantifying the radiative and kinetic efficiencies of Active Galactic Nuclei"
In the context of the co-evolution of supermassive black holes (SMBHs) and galaxies, two parameters are of paramount importance, the radiative and kinetic efficiencies which are believed to regulate the overall bolometric output and jet power of Active Galactic Nuclei (AGN), respectively, and are ultimately responsible for the amount of quasar- and radio-mode AGN feedback on the host galaxies. In this talk, I will describe the latest constraints on these two parameters. I will start by describing the classical Soltan argument, through which one can devise the radiative efficiency from the match between the local SMBH mass function and the SMBH mass function obtained via direct integration of the AGN luminosity function. I will then move on presenting the empirical method we followed to constrain the kinetic efficiency via the match between the optical/X-ray and radio AGN luminosity functions. I will highlight current tensions and possible resolutions in these methodologies that are revealing important insights into SMBH demography.