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Published December 2000 | Accepted Version + Published
Journal Article Open

High Spatial Resolution Imaging of NGC 1068 in the Mid-Infrared


Mid-infrared observations of the central source of NGC 1068 have been obtained with a spatial resolution in the deconvolved image of 0."1 (~7 pc). The central source is extended by ~1'' in the north-south direction but appears unresolved in the east-west direction over most of its length. About 2/3 of its flux can be ascribed to a core structure that is itself elongated north-south and does not show a distinct unresolved compact source. The source is strongly asymmetric, extending significantly farther to the north than to the south. The morphology of the mid-infrared emission appears similar to that of the radio jet and has features which correlate with the images in [O III]. Its 12.5–24.5 μm color temperature ranges from 215 to 260 K and does not decrease smoothly with distance from the core. Silicate absorption is strongest in the core and to the south and is small in the north. The core, apparently containing 2/3 of the bolometric luminosity of the inner 4'' diameter area, may be explained by a thick, dusty torus near the central active galactic nucleus (AGN) viewed at an angle of ~65° to its plane. There are, however, detailed difficulties with existing models, especially the narrow east-west width of the thin extended mid-infrared "tongue" to the north of the core. We interpret the tongue as reprocessed visual and ultraviolet radiation that is strongly beamed and that originates in the AGN.

Additional Information

© 2000 American Astronomical Society. Received 2000 July 21; accepted 2000 September 6. We thank the staff of the Keck Observatory, especially Bob Goodrich, for their assistance in making these observations possible. We also thank Pat Shopbell for discussions about the X-ray observations of NGC 1068 and Lee Armus, Bob Goodrich, Nick Scoville, Kris Sellgren, and Dave Thompson for discussions about various aspects of the interpretation. We thank Ski Antonnucci and Makoto Kisimoto for their helpful comments as referees. The W. M. Keck Observatory is operated as a scientific partnership between the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. It was made possible by the generous financial support of the W. M. Keck Foundation. B. T. S., G. N., K. M., and E. E. are supported by grants from the NSF and NASA. B. T. S. is supported by the SIRTF Science Center at Caltech. SIRTF is carried out at J.P.L., operated by Caltech under an agreement with NASA. This work was carried out in part (J. J. B., M. W. W., and M. E. R.) at J.P.L. The development of MIRLIN was supported by NASA's Office of Space Science.

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Published - Bock_2000_AJ_120_2904.pdf

Accepted Version - 0009078


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