The Redshift Distribution of Flat-Spectrum Radio Sources
Abstract
The redshift distribution of flat-spectrum radio sources with 5 GHz flux densities S>5 mJy is a key component in using current radio lens surveys to probe the cosmological model. We have constructed the first flat-spectrum radio sample in the flux density range 3-20 mJy. Our new sample has 33 sources; we have determined the redshifts of 14 of these (42% complete). The low mean redshift, <z>~0.75, of our faintest sample needs to be confirmed by further observations to improve the sample completeness. We also increased the redshift completeness of several surveys of brighter flat-spectrum sources. While the mean redshift, <z>~1.1 of flat-spectrum samples fainter than 1 Jy is nearly constant, the fraction of the sources identifiable as quasars steadily drops from ~80% to ~10% as the flux density of the sources decreases.
Keywords
Cite
@article{arxiv.astro-ph/0305382,
title = {The Redshift Distribution of Flat-Spectrum Radio Sources},
author = {J. A. Munoz and E. E. Falco and C. S. Kochanek and J. Lehar and E. Mediavilla},
journal= {arXiv preprint arXiv:astro-ph/0305382},
year = {2009}
}
Comments
26 pages with 4 figures, accepted for publication in ApJ