30 GHz flux density measurements of the Caltech-Jodrell flat-spectrum sources with OCRA-p (Research Note)

Aims. To measure the 30-GHz flux densities of the 293 sources in the Caltech-Jodrell Bank flat-spectrum (CJF) sample. The measurements are part of an ongoing programme to measure the spectral energy distributions of flat spectrum radio sources and to correlate them with the milliarcsecond structures from VLBI and other measured astrophysical properties. Methods. The 30-GHz data were obtained with a twin-beam di. erencing radiometer system mounted on the Torun 32-m telescope. The system has an angular resolution of 1.2'. Results. Together with radio spectral data obtained from the literature, the 30-GHz data have enabled us to identify 42 of the CJF sources as Giga-hertz Peaked Spectrum (GPS) sources. Seventeen percent of the sources have rising spectra (a > 0) between 5 and 30 GHz.