Publications of the MPIfR
Optical & Infrared
Interferometry Group
Weigelt, G.; Beckert, T.; Schertl,
K.-H. Hofmann D.; Wittkowski, M.
Near-infrared interferometry of AGN
Memorie della Societa Astronomica Italiana, v.76,
p.39 (2005)
Abstract
Interferometry in the infrared is able to resolve the sub-parsec-scale dust environment surrounding the accretion disk of AGN. A diffraction-limited K'-band image of NGC
1068 with 74 mas resolution and the first H-band image with 57 mas resolution were reconstructed from speckle interferograms obtained with the SAO 6 m telescope. The
resolved structure consists of a compact core and an extended northern and south-eastern component. The compact core has a north-western, tail-shaped extension. The K'-band
FWHM diameter of this compact core is approximately 18 × 39 mas (± 4 mas) or 1.3 × 2.8 pc, and the position angle (PA) of the north-western extension is -16o. The PA of
-16o is similar to that of the western wall of the ionization cone. This suggests that the H- and K'-band emission from the compact core is both thermal emission and
scattered light from dust near the western wall of a low-density, conical outflow cavity or from the innermost region of a parsec-scale dusty torus. The first K-band
long-baseline interferometry of the nucleus of NGC 1068 with resolution lambda /B ˜ 10 mas was obtained with the ESO VLTI. A squared visibility amplitude of 16 ± 4% was
measured at a baseline of 46 m. Taking into account K-band speckle interferometry observations, the VLTI observations suggest a multi-component structure, where part of
the flux originates from scales clearly smaller than ˜ 5 mas or 0.4 pc.
Based on public commissioning data released from the VLTI and data collected at the SAO 6 m telescope in Russia.
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