A Study of Warm IRAS Seyfert Galaxies

The properties of galaxies with abnormally blue 25 micron to 60 micron flux ratios ("warm" galaxies) are discussed. It is shown that, after exclusion of previously known Seyferts from the sample, more than 70% of galaxies with F_60_/F_25_ <= 3 for which optical spectroscopy is available are Seyfert galaxies and that most are of type 2. It should be possible to discover ~130 new Seyferts in this way, all detected by IRAS at 25 microns and lying more than 30^deg^ from the Galactic plane. The space density of Seyfert galaxies which do and do not meet this color criterion is discussed. The newly discovered type 2 Seyferts have a space density comparable to known Markarian Seyfert galaxies but less than type 2 Seyferts in the CfA redshift survey. The 25 micron emission of most Seyferts appears to be dominated by their nuclei, while much evidence from this work and previous studies indicates Seyferts with steeply rising far-infrared spectra ("cold" Seyferts) are dominated by star-formation regions at 60 microns and 100 microns. We find that the cold Seyferts have significantly lower 25 micron luminosities, which is consistent with these ideas. The nuclear optical emission-line ratios of cold type 2 Seyferts are intermediate between those of warm Seyferts and H II regions, suggesting regions of massive star formation exist in the immediate vicinity of the nucleus.