Distribution of dust clouds around the central engine of NGC 1068.
TOMONO D., TERADA H. and KOBAYASHI N.
Abstract (from CDS):
We studied the distribution of dust clouds around the central engine of NGC 1068 based on shifted and added 8.8-12.3 µm (MIR) multifilter images and 3.0-3.9 µm (L-band) spectra obtained with the Subaru Telescope. In a region of 100 pc (1".4) around the central peak, we successfully constructed maps of color temperatures and emissivities of the MIR and L-band continua as well as the 9.7 and 3.4 µm dust features with spatial resolutions of 26 pc (0".37) in the MIR and 22 pc (0".3) in the L band. Our main results are the following: (1) The color temperature of the MIR continuum scatters around the thermal equilibrium temperature with the central engine as the heat source, while that of the L-band continuum is higher and independent of distance from the central engine. (2) The peak of the 9.7 µm silicate absorption feature is shifted to a longer wavelength at some locations. (3) The ratio of the optical depths of the dust features is different from the Galactic values and shows a complicated spatial distribution. (4) There is a pie-shaped warm dust cloud as an enhancement in the emissivity of the MIR continuum extending about 50 pc to the north from the central engine. We speculate that material falls into the central engine through this cloud.
Galaxies: Active - Galaxies: Individual: NGC Number: NGC 1068 - Galaxies: Nuclei - Galaxies: Seyfert - Infrared: Galaxies