AGN on the Beach


The link between circumnuclear molecular gas reservoirs, millimetre continua and active galactic nucleus fuelling

Jacob Elford

 Mo, 12:5 ! Livein  Palazzo Santa Chiarafor  15min

Supermassive black holes (SMBHs) exist in almost all massive galaxies, and accretion of material onto these SMBHs is known to power active galactic nuclei (AGN). In this talk, I will the present results obtained by analysing ALMA data of a diverse sample of 35 nearby galaxies to study the link between circumnuclear (≤100pc) molecular gas reservoirs and AGN fuelling to better understand the powering mechanism. We find that the cold molecular gas mass within the nuclear regions does not correlate with any measure of AGN activity. This suggests that the AGN fuelling is not a ubiquitous process, even when cold gas is present. I will then discuss the origin of the nuclear mm emission in these sources. We find a strong relation between the nuclear mm emission from our galaxies and the SMBH mass, and an even tighter correlation is observed if the 2-10 keV X-ray emission is included. Classic torus models cannot explain the existence of the observed correlations, that we find instead naturally arising from advection-dominated accretion flows (ADAFs). This result suggests that radiatively-inefficient processes are ongoing in our sources (spanning a wide range of AGN types), and provides a new method to indirectly measure SMBH masses.

 Overview  Program