How to Feed AGN: The NUGA View

摘要

NUGA is a high-resolution (0.5–1) CO survey of low luminosity AGN (LLAGN) including the full sequence of activity types (Seyferts, LINERs and transition objects). This project aims at systematically studying the different mechanisms for gas fueling of AGNs in the Local Universe. We discuss the latest results of this recently completed survey. Information on the stellar potentials in NUGA targets is obtained from available HST and ground-based optical/NIR images. This multi-wavelength strategy allows us to test the efficiency of AGN feeding mechanisms by a direct determination of the stellar gravitational torques exerted on the gas. We discuss results obtained in 4 case studies for NUGA, which allow us to track down the feeding history along the Transition/LINER/Seyfert sequence: NGC 4321 (HII/transition object), NGC 4579 (L1.9/S1.9), NGC 4826 (transition object) and NGC 6951 (S2), We derive the general implications of these results for the current understanding of AGN feeding in the Local Universe.