For all types of active galaxies, the most representative measure of total flux is the mid-infrared flux. The 12 micron flux is about one-fifth of the bolometric flux for Seyfert 2 galaxies, Seyfert 1 galaxies, and quasars. Therefore, we selected from the IRAS Point Source Catalog (PSC-2), an all-sky 12 micron flux-limited sample. To obtain a sample of 390 galaxies, a flux limit of 0.3 Jy was required. The incompleteness at low fluxes of the PSC-2 was determined by several techniques, all of which gave consistent results. Most of the sample galaxies are in existing catalogs, and 99% have measured redshifts. The 12 micron and the far-infrared luminosity functions of active and normal galaxies, corrected for incompleteness, have been derived using IRAS co-added data. Twenty-two percent of the sample galaxies harbor active nuclei. This new, large, and complete sample of bright active galaxies consists almost equally of Seyfert 1, Seyfert 2, and LINER nuclei. Our luminosity functions for Seyfert 1 and Seyfert 2 galaxies are indistinguishable from those of the optically selected CfA sample. Thus 12 micron selection is the most efficient available technique for finding complete active galaxy samples.
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Spinoglio et al. (1989) studied this question.