Publication

Redshifts of class radio sources

Marlow, DR., Rusin, D., Jackson, N., Wilkinson, PN., Browne, IWA. & Koopmans, L., Jun-2000, In : The Astronomical Journal. 119, 6, p. 2629-2633 5 p.

Research output: Contribution to journalArticleAcademicpeer-review

  • DR Marlow
  • D Rusin
  • N Jackson
  • PN Wilkinson
  • IWA Browne
  • L Koopmans

Spectroscopic observations of a sample of 42 flat-spectrum radio sources from the Cosmic Lens All-Sky Survey (CLASS) have yielded a mean redshift of (z) = 1.27 with an rms spread of 0.95, at a completeness level of 64%. The sample consists of sources with a 5 GHz flux density of 25-50 mJy, making it the faintest flat-spectrum radio sample for which the redshift distribution has been studied. The spectra, obtained with the William Herschel Telescope, consist mainly of broad-line quasars at z > 1 and narrow-line galaxies at z <0.5. Though the mean redshift of flat-spectrum radio sources exhibits little variation over more than 2 orders of magnitude in radio flux density, there is evidence of a decreasing fraction of quasars at weaker flux levels. We present the results of our spectroscopic observations and discuss the implications for constraining cosmological parameters with statistical analyses of CLASS.

Original languageEnglish
Pages (from-to)2629-2633
Number of pages5
JournalThe Astronomical Journal
Volume119
Issue number6
Publication statusPublished - Jun-2000

    Keywords

  • gravitational lensing, PHASE CALIBRATION SOURCES, VLA ASTROMETRIC SURVEY, CATALOG

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