Speaker
Leonard Burtscher
(MPE)
Description
Interferometric observations with MIDI/VLTI in the mid-infrared made studies of the central dusty tori of Active Galactic Nuclei (AGNs) possible and proved their existence in a few nearby galaxies. In an effort to enhance the existing sample to a number that would allow statistical questions to be asked, we have now completed a MIDI Large Programme comprising 16 nights of VLTI/UT time. The results are surprising: Most AGNs are more compact than expected from applying simple scaling relations to the two well studied MIDI sources NGC 1068 and the Circinus galaxy and only a small fraction of sources shows measurable elongations. Compiling the measured radii to a "size-luminosity" plot of AGN tori reveals that it is flatter than originally thought. More importantly, the scatter in this relation is large and therefore not consistent with simple unified torus models. The new picture emerging from these observations is a view of complex and individual mid-infrared emitters in AGNs.
Author
Leonard Burtscher
(MPE)