Contributed Talk - Splinter SMBHs

Wednesday, 23 September 2020, 14:40   (virtual room K)

Resolving AGN broad line regions with the near-infrared VLTI/GRAVITY interferometer

GRAVITY Collaboration
Max Planck Institute for Extraterrestrial Physics

I will present spatially resolved kinematics of the broad line region (BLR) in three active galactic nuclei (AGNs), which we have modelled to infer the BLR structure and black hole mass. This has been made possible by the VLTI/GRAVITY instrument, which has proven that near-infrared interferometry is a powerful tool to probe the innermost regions of AGN on sub-parsec scales. In this talk, I will introduce the GRAVITY observation and data reduction to derive the spectro-astrometric measurements. I will present the analyses on 3C 273, IRAS 09149-6206, and NGC 3783 to discuss the current methods and challenges to infer the BLR geometry and kinematics. Clear photocenter offsets are observed between the spectral channels on the blue and red sides of the broad emission lines. Different BLR kinematics, dominated by the orbital motion or radial motion, can be inferred from the data. Our measured BLR radii are generally consistent with the radius-luminosity relation established by the reverberation campaigns of low redshift AGNs.