High‐Resolution Mid‐Infrared Morphology of Cygnus A

We present subarcsecond resolution mid-infrared images at 10.8 and 18.2microns of Cygnus A. These images were obtained with the University of Floridamid-IR camera/spectrometer OSCIR at the Keck II 10-m telescope. Our data showextended mid-IR emission primarily to the east of the nucleus with a possiblewestern extension detected after image deconvolution. This extended emission isclosely aligned with the bi-conical structure observed at optical and near-IRwavelengths by the HST. This emission is consistent with dust heated from thecentral engine of Cygnus A. We also marginally detect large-scale low levelemission extending > 1.5 kpc from the nucleus which may be caused by in-situstar formation, line emission, and/or PAH contamination within the bandpass ofour wide N-band filter.Comment: 20 pages, 8 figures, accepted for publication in the Astrophysical Journa