High-Resolution Mid-Infrared Morphology of Cygnus A

We present subarcsecond-resolution mid-infrared images at 10.8 and 18.2 μm of Cyg A. These images were obtained with the University of Florida mid-IR camera/spectrometer OSCIR at the Keck II 10 m telescope. Our data show extended mid-IR emission primarily to the east of the nucleus with a possible western extension detected after image deconvolution. This extended emission is closely aligned with the biconical structure observed at optical and near-IR wavelengths by the Hubble Space Telescope. This emission is consistent with dust heated from the central engine of Cyg A. We also marginally detect large-scale low-level emission extending more than 1.5 kpc from the nucleus, which may be caused by in situ star formation, line emission, and/or polycyclic aromatic hydrocarbon contamination within the bandpass of our wide N-band filter.