2012A&A...541L...9W

The putative tori surrounding the accretion disks of active galactic nuclei (AGNs) play a fundamental role in the unification scheme of AGNs. Infrared long-baseline interferometry allows us to study the inner dust distribution in AGNs with unprecedented spatial resolution over a wide infrared wavelength range. Near- and mid-infrared interferometry is used to investigate the milli-arcsecond-scale dust distribution in the type 1.5 Seyfert nucleus of NGC 3783. We observed NGC 3783 with the VLTI/AMBER instrument in the K-band and compared our observations with models. From the K-band observations, we derive a ring-fit torus radius of 0.74±0.23mas or 0.16±0.05pc. We compare this size with infrared interferometric observations of other AGNs and UV/optical-infrared reverberation measurements. For the interpretation of our observations, we simultaneously model our near- and mid-infrared visibilities and the spectral energy distribution (SED) with a temperature/density-gradient model including an additional inner hot 1400 K ring component.