VLTI/AMBER observations of the Seyfert nucleus of NGC 3783

TL;DR

This study uses infrared interferometry to measure the dust distribution in the Seyfert galaxy NGC 3783, revealing a ring-like torus structure at sub-parsec scales and comparing it with other AGN observations.

Contribution

First near- and mid-infrared interferometric measurements of NGC 3783's dust distribution, modeling the structure with a temperature/density gradient and an inner hot ring.

Findings

Derived a torus radius of 0.16 pc from K-band data

Compared dust size with other AGNs and reverberation measurements

Modeled the dust structure including an inner hot ring

Abstract

Context. 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. Aims. 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. Methods. We observed NGC 3783 with the VLTI/AMBER instrument in the K-band and compared our observations with models. Results. From the K-band observations, we derive a ring-fit torus radius of 0.74 +/- 0.23 mas or 0.16 +/- 0.05 pc. 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 SED with a temperature/density-gradient model including an additional inner hot 1400 K ring component.