A new analysis of the nucleus of NGC 1068 with MIDI observations
LUTH, Observatoire de Paris, 92195 Meudon Cedex, France
2 LESIA, Observatoire de Paris, 92195 Meudon Cedex, France e-mail: email@example.com
Accepted: 18 December 2005
We present a new analysis of the first mid-infrared N-band long-baseline interferometric observations of an extragalactic source: the nucleus of the Seyfert 2 galaxy NGC 1068, obtained with MIDI (Mid-InfrareD Interferometer), the mid-infrared beamcombiner at the European Southern Observatory (ESO) Very Large Telescope Interferometer (VLTI). The resolution of mas allows us to study the compact central core of the galaxy between 8 and 13 μm. Both visibility measurements and MIDI spectrum are well reproduced by a simple radiative transfer model with two concentric spherical components. The derived angular sizes and temperatures are ~35 and 83 mas, and ~361 K and 226 K for these two components respectively. Other evidence strongly supports such low temperatures. This modeling also provides the variation of optical depth as a function of wavelength for the extended component across the N-band suggesting the presence of amorphous silicate grains. This shows that MIDI has carried out the first direct observations of the distribution of dust around the central engine.
Key words: galaxies: individual: NGC 1068 / galaxies: Seyfert / galaxies: nuclei / radiative transfer / infrared: galaxies / techniques: interferometic
© ESO, 2006