Dynamic Spectra of Low-Frequency Variables

A wide range of models have been proposed to account for low-frequency (≲ 1 GHz) variability in cosmologically-distant radio sources. To address these models we (Payne et al. 1982) are monitoring the 0.3–1.4 GHz spectra of such sources. Results from three years of monitoring indicate that two distinct types of low-frequency variables may exist.