Resolving the central parsecs of AGN through cosmic time: Implications of recent GRAVITY+ observations at z=2-4 on AGN structure and feedback

In this talk, I present recent observational insights on AGN structure and feedback at z=2-4 on parsec to sub-parsec scales, made possible by interferometric spectro-astrometry with GRAVITY and its recent upgrade, GRAVITY+. First, by spatially resolving the Broad Line Region (BLR) kinematics, we obtain the most precise direct black hole mass estimates in those epochs so far. I will compare these to masses derived from common virial estimators widely used at high redshift with JWST. Second, our studies reveal significant outflow components from the BLR, providing key insights into outflow origin and structure. I will show how this BLR outflow component varies as a function of AGN properties, and discuss the implications for this feedback driving mechanism. Further, we have for the first time successfully resolved the [OIII] emitting region interferometrically on tens-of-parsec scales at z=3.3. Combined with the kinematically resolved broad H-beta, this allows us to trace gas motion from sub-parsec scales out to its immediate surroundings. I will discuss these new insights in the context of AGN feedback and a potential connection to larger scales. Together, these novel GRAVITY+ observations provide a unique view of AGN feedback at ~parsec scales at high redshift, tracing it from its very origin. Additionally, they can serve as calibrators for larger studies and as constraints for numerical simulations.