The ISO-IRAS Faint Galaxy Survey: Early results

We present preliminary results for AGNs and starburst galaxies the ISO-IRAS Faint Galaxy Survey (IIFGS). The goal of the survey is to produce a database of infrared-luminous galaxies at redshifts of about 0.1–1 to help explore the AGN-starburst relationship, study the cosmological evolution of luminous infrared galaxies, and identify possible protogalaxy candidates. The candidate list of $∼3700$ sources has been extracted from the IRAS Faint Source Survey using criteria selecting for faint, infrared-bright galaxies. The ISO observations will confirm the IRAS detections, yield sensitive 12 & 90 μm fluxes, and provide positions to $∼6′′$ accuracy which will allow unambiguous optical identifications. Confirmed sources are being followed up with ground-based observations to determine optical magnitudes and accurate redshifts. In this preliminary phase we have in hand $∼100$ observed fields and are developing techniques to maximize the sensitivity of the observations. Early results for the ISOCAM 12 μm images indicate we can reliably detect sources as faint as $∼0.5 mJy;$ $∼80%$ of the fields contain at least one source.