Active Galactic Nuclei: fueling and feedback

Main Colloquium
Prof. Françoise Combes
Observatoire de Paris and Collège de France, Paris, France

Dynamical mechanisms are essential to exchange angular momentum in galaxies, drive the gas to the center, and fuel the central super-massive black holes. While at 100 pc scale, the gas is sometimes stalled in nuclear rings, recent observations reaching 10 pc scale, or 60 mas with ALMA, have revealed, within the sphere of influence of the black hole, smoking gun evidence of fueling. Observations of AGN feedback will be described, together with the suspected responsible mechanisms. Molecular outflows are frequently detected in active galaxies with ALMA and NOEMA, with loading factors between 1 and 5. When driven by AGN with escape velocity, these outflows are therefore a clear way to moderate or suppress star formation. Molecular disks, or tori, are detected at 10 pc-scale, kinematically decoupled from their host disk, with random orientation. They can be used to measure the black hole mass.