1997A&A...325..450S

We present infrared and millimeter-wave observations of the Circinus galaxy which is at a distance of only 4 Mpc and provides the closest example of an obscured Seyfert nucleus surrounded by a starburst ring. The FWHM size of the continuum emission is found to be only ≃0.3" (6pc) at 3-5µm, ≃1.3" at 10µm, ≤1.5" at 20µm and ≤23" (460pc) at 1.3mm. The 1.3mm measurements also provide an estimate of ≃1.6x10⁸M_☉ for the gas mass. It is shown using a radiative transfer code that both the observed sizes and overall spectral energy distribution, including the 9.7µm silicate absorption and 3.28-11.3µm PAH emission features, can be satisfactorily modelled by assuming that the total luminosity is dominated by dust heated by a central power law source.