An atlas of warm active galactic nuclei and starbursts from the IRAS deep fields
We present a set of 180 active galactic nucleus (AGN) candidates based on color selection from the IRAS slow-scan deep observations, with color criteria broadened from the initial Point Source Catalog samples so as to include similar objects with redshifts up to z = 1 and allowing for two-band detections. Spectroscopic identifications have been obtained for 80 (44%); some additional identifications are secure based on radio detections or optical morphology, although yet unobserved spectroscopically. These spectroscopic identifications include 13 type 1 Seyfert galaxies, 17 type 2 Seyferts, 29 starburst galaxies, 7 LINER systems, and 13 emission-line galaxies so heavily reddened as to remain of ambiguous classification. The optical magnitudes range from R = 12.0 to 20.5; the counts suggest that incompleteness is important fainter than R = 15.5. Redshifts extend to z = 0.51, with a significant part of the sample at z > 0.2. Even with the relaxed color criteria, this sample includes slightly more AGNs than star-forming systems among those where the spectra contain enough diagnostic feature to make the distinction. The active nuclei include several broad-line objects with strong Fe II emission, and composite objects with the absorption-line signatures of fading starbursts. These AGNs with warm far-IR colors have little overlap with the "red AGNs'' identified with 2MASS; only a single Seyfert 1 was detected by 2MASS with J - K > 2. Some reliable IRAS detections have either very faint optical counterparts or only absorption-line galaxies, potentially being deeply obscured AGNs. The IRAS detections include a newly identified symbiotic star, and several possible examples of the "Vega phenomenon,'' including dwarfs as cool as type K. Appendices detail these candidate stars, and the optical-identification content of a particularly deep set of high-latitude IRAS scans ( probing the limits of optical identification from IRAS data alone).