Contributed Talk - Splinter SMBHs

Wednesday, 23 September 2020, 14:25   (virtual room K)

The resolved size and structure of hot dust around AGN with VLTI/Gravity


I will present results on our study of the size and structure of hot dust in AGN using VLTI/GRAVITY. Through our Large Program, we have measured Gaussian FWHM sizes for 8 Type 1 AGN in K-band, nearly doubling the number of NIR interferometric size measurements. We find sizes between 0.1 -- 1.3 pc with no strong evidence for significant elongations or asymmetries except in one case (NGC 3783). As found in previous studies, our sizes increase with AGN bolometric luminosity, however there is evidence for a deviation from the expected R ~ L^1/2 relationship at quasar luminosities which could suggest an evolution of the hot dust structure as a function of luminosity. I will also present our fully resolved image of the hot dust in NGC 1068, a classic Type 2 AGN, where we find a ring-like structure with a radius of 0.24 pc and inclination of 70 deg that is consistent with the dust sublimation region. With an H/R ~ 0.14, the ring is inconsistent with a geometrically and optically thick torus and instead seems to be associated with the 22 GHz maser disc. Together, these results show how long baseline NIR interferometry with GRAVITY is now beginning to reveal the the sub-parsec scale structure of gas and dust structures around AGN.