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The Westerbork Northern Sky Survey (WENSS) has been used to select a sampleof Gigahertz Peaked Spectrum (GPS) radio sources at flux densities one to twoorders of magnitude lower than bright GPS sources investigated in earlierstudies. Sources with inverted spectra at frequencies above 325 MHz have beenobserved with the WSRT at 1.4 and 5 GHz and with the VLA at 8.6 and 15 GHz toselect genuine GPS sources. This has resulted in a sample of 47 GPS sourceswith peak frequencies ranging from ~500 MHz to >15 GHz, and peak flux densitiesranging from ~40 to ~900 mJy. Counts of GPS sources in our sample as a functionof flux density have been compared with counts of large scale sources fromWENSS scaled to 2 GHz, the typical peak frequency of our GPS sources. Thecounts can be made similar if the number of large scale sources at 2 GHz isdivided by 250, and their flux densities increase by a factor of 10. On thescenario that all GPS sources evolve into large scale radio sources, theseresults show that the lifetime of a typical GPS source is ~250 times shorterthan a typical large scale radio source, and that the source luminosity mustdecrease by a factor of ~10 in evolving from GPS to large scale radio source.However, we note that the redshift distributions of GPS and large scale radiosources are different and that this hampers a direct and straightforwardinterpretation of the source counts. Further modeling of radio source evolutioncombined with cosmological evolution of the radio luminosity function for largesources is required.

A new sample of faint Gigahertz Peaked Spectrum radio sources