2003/05/20 by J. A. Munoz, J. A. Muñoz, E. E. Falco +5 · 1 citation
Physics and Astronomy · #Galaxies: Formation, Evolution, Phenomena #Gamma-ray bursts and supernovae #Radio Astronomy Observations and Technology #astro-ph
paper · pdf · doi:10.1086/377077
published as Astrophys.J. 594 (2003) 684-694 · 26 pages with 4 figures, accepted for publication in ApJ
arxiv created 2003/05/20 · openalex publication_date 2003/09/05 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
The redshift distribution of flat-spectrum radio sources with 5 GHz flux densities S 5 ≳ 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.