A continuum radio survey of isolated galaxies

The results of a radio continuum survey of isolated galaxies from the KI catalog at 5 GHz with a 300-ft telescope are discussed with reference to the hypothesis that the isolated environment of these galaxies leads to a deficiency of radio sources. Of the 120 E/SO's and 400 spirals surveyed, only one and ten detections, respectively, were made above 20 mJy. By constructing fractional radio luminosity functions for this and two other similar samples, it is shown that the isolated galaxies are extremely deficient in radio sources relative to galaxies in denser regions of space. These results are briefly interpreted in terms of a 'scenario' for radio source production in which the internal gas supply is determined by the external environment.