A new sample of faint Gigahertz Peaked Spectrum radio sources

Abstract

Abstract. The Westerbork Northern Sky Survey (WENSS) has been used to select a sample of Gigahertz Peaked Spectrum (GPS) radio sources at flux densities one to two orders of magnitude lower than bright GPS sources investigated in earlier studies. Sources with inverted spectra at frequencies above 325 MHz have been observed with the WSRT at 1.4 and 5 GHz and with the VLA at 8.6 and 15 GHz to select genuine GPS sources. This has resulted in a sample of 47 GPS sources with peak frequencies ranging from ∼500 MHz to > 15 GHz, and peak flux densities ranging from ∼40 to ∼900 mJy. Counts of GPS sources in our sample as a function of flux density have been compared with counts of large scale sources from WENSS scaled to 2 GHz, the typical peak frequency of our GPS sources. The counts can be made similar if the number of large scale sources at 2 GHz is divided by 250, and their flux densities increase by a factor of 10. On the scenario that all GPS sources evolve into large scale radio sources, these results show that the lifetime of a typical GPS source is ∼250 times shorter than a typical large scale radio source, and that the source luminosity must decrease 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 radio sources are different and that this hampers a direct and straightforward interpretation of the source counts. Further modeling of radio source evolution combined withThe Westerbork Synthesis Radio telescope (WSRT) is operated by the Netherlands Foundation for Research in Astronomy with financial support from the Netherlands Organisation for Scientific Research (NWO).The Very Large Array (VLA) is operated by the U.S. National Radio Astronomy Observatory which is operated by the Associated Universities, Inc. under cooperative agreement with the National Science Foundation. cosmological evolution of the radio luminosity function for large sources is required.

Multifrequency VLBA observations of two compact symmetric objects

“…The flux density decreases from the C to the X band. The literature information confirm that J1944+5448 has a turnover at low frequency, around 1 GHz (Snellen et al, 1998). The total radio spectrum of this source is shown in Fig.…”

“…Compact radio sources can be simply described as a scaled-down version (with physical size from 0.01 to ⇠15 kpc) of the powerful, edge-brightened FRII (Snellen et al, 1998).…”

Connecting X-ray absorption and 21 cm neutral hydrogen absorption in obscured radio AGN

“…Sp is the flux density at the peak frequency νp (Snellen et al 1998). The standard non-thermal synchrotron power-law of the form…”

NH‐NHI correlation in gigahertz‐peaked‐spectrum galaxies

“…This sample is composed of 21 sources, belonging to at least one of the following GPS samples: Stanghellini et al (1998), Snellen et al (1998), Torniainen et al (2007), and Vermeulen et al (2003). All of these sources were also classified as CSOs.…”