A VLBI and MERLIN Survey of faint, compact radio sources

Abstract

We present preliminary results from a VLBI survey at $\lambda =6$cm of a sample of 35 sources with flux densities of 2 - 100 mJy. These sources were selected from the VLA FIRST survey at $\lambda =20$cm, in a 3 degree field around the bright calibrator 1156+295, simply by imposing $S_{20}>10$ mJy and $\theta <5$ arcsec. MERLIN observations at $\lambda 6$cm detected 70/127 of these sources with a threshold of 2 mJy at 50 mas resolution and the closest 35 of these to the calibrator were observed with the VLBA+EVN in snapshot mode at $\lambda 6$cm. These sources are a mixture of flat and steep-spectrum sources and include: weak flat-spectrum nuclei of large radio galaxies, low power AGN in nearby galaxies and radio quiet quasars. With these short observations, the sensitivity is limited and most appear as either core-jets or simple point sources on the milliarcsec scale. Nonetheless, it is encouraging that with only 10 minutes observation per source, at least 35% of all sources with $S_{20}>10$ mJy can be detected and imaged with global 6cm VLBI.

6 pages, 3 figures, to appear in New Astronomy Reviews (EVN/JIVE Symposium No. 4, special issue) Colour figures and further background information available at the project web site: http://www.nfra.nl/~mag/first.html

References in corpus (1)

• Limits on Cosmological Models From Radio-Selected Gravitational Lenses

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