Marecki et al., A new sample of GPS sources

A new sample of GPS sources

A. Marecki(1), J. Niezgoda(1), H. Falcke(2), S. T. Garrington(3), A. R. Patnaik(4)

(1) TRAO, N. Copernicus University, Torun, Poland (
(2) Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (
(3) NRAL, Jodrell Bank, UK
(4) MPIfR, Bonn, Germany

to appear in the Proceedings of the 2nd Workshop on GPS and CSS radio sources, Leiden 1996


Using four published catalogues we have compiled a new sample of compact sources that apparently exhibit a spectral turnover at GHz frequencies. For most of these sources the flux densities at low frequencies (~ 400 MHz) were not available so the convex shape of their spectra was based on a crude extrapolation of L, C, and X-band data. In order to determine the spectral turnovers accurately and to exclude any flat spectrum sources we successfully measured fluxes of 100 objects at 408 MHz with MERLIN. So far we knew that 37 sources in the MERLIN phase calibrator list by Patnaik et al. (1992) were actually GPS sources rather than typical flat spectrum sources. With these observations we increased that number to 117 (i.e. every 7th source).

Paper: Available in full length as PostScript and LaTex (AAS) Format.

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Questions: Heino Falcke,