RADIO PROPERTIES OF EXTRAGALACTIC IRAS SOURCES

Extragalactic sources with S60-mu-m greater-than-or-equal-to 0.2 Jy and alpha(12-mu-m, 60-mu-m) greater-than-or-equal-to 0 from the IRAS Faint Source Catalog Version 1 covering \b\ > 50-degrees were identified by position coincidence with radio sources stronger than S = 25 mJy and lying north of delta = + 5-degrees on the Green Bank 4.85 GHz sky maps. There are N = 7702 far-infrared (FIR) sources and N approximately 1.3 x 10(4) radio sources in this OMEGA approximately 1.28 sr area. Published VLA maps, new 4.86 GHz VLA maps made with 15 arcsec resolution, and accurate optical positions were used to confirm 122 of these candidate identifications. Normal and starburst spiral galaxies comprise approximately 97% of the FIR flux-limited sample. Their logarithmic FIR/radio flux-density ratio distribution is quite narrow (sigma-q = 0.14 +/- 0.02) with mean <q> = 2.75 +/- 0.03, and all are relatively cool [alpha(25-mu-m, 60-mu-m) greater-than-or-similar-to + 1.5] FIR sources. Radio-loud "monsters" with q < 2.25 dominate the radio emission from about 2% of the FIR source sample, and radio-quiet monsters are responsible for the FIR emission from less-than-or-similar-to 1% of the FIR sample. The FIR emission from the two BL Lac objects identified, B2 1308 + 32 and OQ 530, is nonthermal; the remaining identifications all appear to be thermal FIR sources. A significant fraction of the thermal FIR sources in radio-loud galaxies are so warm [alpha(25-mu-m, 60-mu-m) < + 1.5] that their heating sources are probably monsters, not starbursts. All of the radio-identified sources are optically identified, mostly with relatively bright nearby galaxies. There is no evidence in our sample for any new populations of high-redshift FIR sources, nonthermal sources with steep FIR/optical spectra, or dust-shrouded sources visible only at FIR and radio wavelengths.