Infrared color-selected quasars and Seyfert 1 galaxies

Abstract

To search for high-luminosity galaxies and quasars, a large sample of warm extragalactic objects (WHO) was selected from the IRAS Point Source Catalog. All sources in an area of 14,000 deg 2 were subjected to an IR color requirement, F(25)/F(60) > 0.25, optimized to find quasars. Based on optical spectra and morphology, the extragalactic sample of 187 sources contains 12 quasars, 27 Seyfert 1, 73 Seyfert 2, and 65 other emission-line galaxies; 10 sources are not yet classified. Seven of the confirmed quasars were discovered by the IRAS survey and indicate that the local space density of these objects may be significantly higher than deduced from current optical searches. Comparison of the distributions of IR luminosity for the quasar and SI samples shows noticeable differences. Larger, more complete samples of these systems are needed to confirm the suggestion of a bimodal luminosity distribution reported here and to refine our knowledge of space densities for these related populations.