  Images at 12.5 microns of nuclei of three nearby Seyfert galaxies -- NGC
1275, NGC 4151 and NGC 7469 -- have been obtained with the Keck 10-m Telescope.
NGC 7469 is resolved and deconvolution delineates a structure <0.04"x0.08" or
<13x26 pc at a position angle of 135deg. From a comparison with structure seen
at millimeter wavelengths, this structure is interpreted as a disk aligned with
the molecular gas in the central few hundred parsecs of the galaxy. NGC 1275
and NGC 4151 are not resolved; limits on the sizes of these nuclei are 0.08"
and 0.16", corresponding to physical spatial scales of 28 and 10 pc. The lower
limits to the brightness temperatures implied by these size limits and the
measured flux densities are within ~50K of the 12 micron to 25 micron color
temperatures of these systems as inferred from IRAS observations. The angular
size limits are within a factor of 2.5 of the sizes required to spatially
resolve thermal emission from dust heated by a central luminosity source. These
sizes preclude significant contributions to the nuclear infrared emission from
star forming regions.
