VLA-FIRST/GB6 inverted-spectrum radio sources at 20 GHz

Abstract Until surveys at higher frequencies are performed, selecting sources with inverted spectra between 1.4 and 4.8 GHz is the most promising method of detecting Gigahertz Peaked Spectrum (GPS) sources that peak above 4.8 GHz. Models of radio source evolution predict the existence of such sources as the precursors to other classes of radio sources. These sources might be a significant foreground for cosmic microwave background anisotropy satellites (such as MAP and Planck). A sample of 308 inverted-spectrum radio sources was selected from the cross-correlation of the VLA FIRST and GB6 surveys. These sources have 1.4–4.8 GHz spectral indices greater than +0.4, where S ν ∝ ν +α . Results from 20 GHz observations taken at the NRAO 140-foot are presented for this sample.