1995A&AS..113..409S

Using the IRAM 30-m telescope, we have measured 90- and 230-GHz flux densities for a sample of 76 sources, about 70 of which are compact steep-spectrum radio sources (CSSs). These flux densities have been used to extend the radio spectra of the CSSs to millimeter wavelengths, and look for deviations of their high-frequency spectra from the trends established at lower frequencies. Since flat-spectrum, cm-wavelength, nuclear components have been detected in some of these sources, it is possible that such radio cores are self-absorbed at cm wavelengths, but could make their presence felt in the mm range via a flattening of the integrated spectrum. Alternatively, if the nucleus is no longer active and there is no fresh supply of energy to the extended features, one might find high-frequency spectral steepening caused by radiative losses. In this paper we present the results of our observations and discuss their implications.