Abstract

Contributed Talk - Splinter Multimessenger

Gas flows in AGN broad line regions from the local universe to beyond cosmic noon

Dieter Lutz (on behalf of the GRAVITY+ consortium AGN team)
MPE Garching

The central parsec of AGN is a key region for the launching of winds and feedback, and near-infrared interferometry is a unique tool for its study. The GRAVITY instrument on the Very Large Telescope Interferometer and its GRAVITY+ upgrade are transforming our ability to study active galactic nuclei and QSOs at unprecedented angular resolution. Near infrared kinematic measurements of recombination lines on 10 microarcsecond scale constrain dynamical models of orbital and radial gas flow around the central supermassive black hole. With wide-angle phase referencing, state-of-the-art adaptive optics, and soon lasers at all four VLT unit telescopes, GRAVITY+ dramatically expands the range of accessible AGNs and opens a new window on high-redshift supermassive black holes. Observations already cover AGN from local Seyferts to QSOs at z~4. We have found that the BLR radius–luminosity relation is shallower than the canonical R~L^0.5 relation. The direct interferometric SMBH mass determinations provide a crucial check on spectroscopic 'single epoch' methods that were previously the only viable method for mass determinations at high redshift. In conjunction with host masses derived from mm interferometry, they test the evolution of the SMBH/host mass ratio. Significant outward radial flows are present in the BLR of some AGN, possibly related to their Eddington ratio.