Radio spectra of Gigahertz Peaked Spectrum radio sources

A well defined sample of 72 Gigahertz Peaked Spectrum radio sources is compiled, having turnover frequencies in the range of 0.5 - 10 GHz. Using this sample, the canonical GPS radio spectrum is constructed, which is found to have a constant shape, independent of AGN type, redshift or radio luminosity. A possible deficiency of low turnover frequencies at high redshift is found, which may reflect a physical mechanism where turnover frequency and radio luminosity are correlated