We have presented new observational evidence that the infrared emission from the Circinus galaxy largely originates within a compact region which increases with wavelength but is only a few pc across at 3.8µm, about 26pc around 10µm and still 460 pc at 1.3mm.
Using a spherically symmetric radiative transfer code we have shown that both the observed size versus wavelength and overall spectral energy distribution are consistent with assuming that the infrared emission is mostly from dust heated by the AGN. The many free parameters in the model appear to be well constrained by the observations. Although the starburst probably contributes to the 100 µm and PAH emission it is interesting that significant PAH feature emission is predicted by the AGN only model.
© European Southern Observatory (ESO) 1997
Online publication: April 28, 1998