The infrared continua of active galaxies

Multi-color, multi-aperture infrared (JHKL) photometry extending in some cases over a period of several years is presented for 24 Seyfert and X-ray emitting southern galaxies. The essential uniformity of the colors of the Seyfert 1 nuclei and their similarity to those of the violently variable quasars is shown for this wavelength region. Using the infrared two-color diagrams, the nuclear colors of the remaining X-ray emitting galaxies are found to be similar after correction for reddening. Further evidence for the universality of the underlying power sources of these galaxies and of quasars is drawn from the ratios of infrared to X-ray fluxes.