2.2. Radio/submillimeter

The radio emission of PG quasars (Kellerman et al. 1989) is significantly different for radio-loud and radio-quiet sources. However, in all cases, the radio emission provides a negligible fraction of the bolometric luminosity. Here we only concentrate on the "core" emission, i.e., the flat spectrum, compact component that is physically distinct from the steep spectrum lobes (however, the angular resolution is not always good enough to separate these components). In radio-loud objects, a strong, non-thermal continuum extends from the radio to the far-infrared through the submillimeter, while in radio-quiet objects, the SED turns over sharply in the far-infrared, with a slope > 2.5 indicative of dust, and the radio emission is only a negligible tail of this component.