The extended mid-infrared structure of the Circinus galaxy

We present subarcsecond resolution mid-IR images of the Circinus galaxy at 8.74 and 18.33 mum. We resolve extended emission at both wavelengths, extending similar to2 from each side of the nucleus in an approximate east-west direction. These extensions are spatially coincident with previously detected compact (similar to30 pc) V-shaped [O III] emission extending northwest of the nucleus as well as countercone [Si VI] emission, emission at these wavelengths interpreted as delineating the interface between inflowing material and the ionization cone. We detect no extended mid-IR emission associated with the structure responsible for collimating the ionizing photons (i.e., obscuring torus or disk of material), limiting the flux density of the obscuring structure to less than or equal to0.27 mJy or a diameter of less than or equal to0.20 (less than or equal to4 pc).