High-Resolution Mid-Infrared Imaging of the Nucleus of NGC 1068

We have obtained mid-infrared images of the nucleus of NGC 1068 from the Hale5 m telescope at Mt. Palomar with diffraction-limited resolution and highsensitivity at 8.8, 10.3, and 12.5 microns. Deconvolved images show that theinfrared emission extends north to south in the inner 2", consisting of acentral peak, a component extending 1" north of the central source, a componentextending 1" south of the central source, and several smaller structureslocated 1" to the northeast. The central peak is extended 0.4" N-S andunresolved (<= 0.2") E-W. We find that 50 +/- 5% of the flux emerges from thecentral 0.4" and that a single unresolved point source can account for only 27+/- 5% of the total flux. However, if the central peak arises from opticallythick emission, we estimate that the emitting region has a projected area >= 2pc^2, and may thus contain a compact source such as a parsec-scale torus. Weobserve a correspondence between the northern extension and the northeasternsources appearing on the mid-infrared images and the [OIII] clouds A-C & E. Weinterpret the faint optical counterpart to the mid-infrared southern extensionas being due to partial obscuration by the intervening disk of the host galaxy.The N-S extension of the mid-infrared emission coincides with one wall of theconical narrow line region and aligns with the N-S orientation of the radio jetclose to the nucleus. We interpret the infrared emission as arising fromoptically thick dust lining the walls of the low density cavity formed by theradio jet and heated by radiation from the central source.Comment: accepted by Astrophysical Journal 29 June 1998, 18 pages, 2 figure