Brightness Distribution in Discrete Radio Sources III. The Structure of the Sources

The visibility functions of 195 radio sources are interpreted in terms of the structure of these sources. Of the 195 sources, 174 are known or presumed to be extragalactic. Seventy-five of these extragalactic sources are resolved with the interferometer spacings used, and complex structure is found in all but 13. In the sources showing complex structure, two similar components with nearly equal intensities are found in 15, 40 show two or more components of unequal intensities, while 7 appear to be a bright core surrounded by a halo. It is suggested that the majority of all extragalactic sources have complex structure. Data are also given on the brightness distributions in the 21 galactic sources observed. In contrast to the extragalactic sources, emission from the galactic sources is typically confined to a single region.