Radio properties of optically selected quasars

K. L. Visnovsky, C. D. Impey, C. B. Foltz, P. C. Hewett, R. J. Weymann, S. L. Morris

Research output: Contribution to journalArticlepeer-review

66 Scopus citations


Radio observations are presented for 124 QSOs from the Large Bright Quasar Survey (LBQS). The QSOs were observed at 8.4 GHz with the Very Large Array (VLA) in the C and C/D hybrid array configurations. An average 3 σ noise limit of 0.255 mJy was reached, allowing 24, or 19%, of the QSOs to be detected. The noise statistics are such that we expect about one spurious 3 σ detection to occur in our sample. The radio detection probability is independent of both redshift and B-magnitude, and the distribution of the parameter R8.4 (radio-to-optical luminosity ratio) is independent of both redshift and absolute magnitude. All of the sources are unresolved. The log R8.4 distribution of the LBQS sample covers nearly four orders of magnitude and appears to be bimodal. Comparisons with the Palomar Bright Quasar Survey (BQS) are hampered by a potential selection effect in the BQS data. Using both samples in a region unaffected by this bias, it appears that the radio-loud fraction of optically selected QSOs decreases with increasing redshift and decreases with fainter absolute magnitude.

Original languageEnglish (US)
Pages (from-to)560-568
Number of pages9
JournalAstrophysical Journal
Issue number2
StatePublished - Jun 1 1992


  • Quasars: general
  • Radio continuum: galaxies
  • Surveys

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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