Differential evolution of radio quiet and radio loud quasars

Maarten Schmidt, J. H. Van Gorkom, Donald P. Schneider, James E. Gunn

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

We have observed 40 optically selected high-redshift quasars with the VLA at 1515 MHz (20 cm). Three quasars are detected above our 3σ limit of 0.2 mJy. We review all available evidence on radio detections of optically selected quasars in terms of their ratio R of radio to optical luminosity. We find that the quasars ranked in the top 5-20 percent in R show strong evolution in their R distribution. We present two interpretations of this phenomenon. The first one poses that the R values decrease by a factor of around 100 from redshift 0.3 to 1.3. In the second interpretation, we consider that there are two populations of quasars, which we call radio silent and radio active, separated by R∼0.1. The radio-silent fraction of quasars increases from ∼16% at redshift 0.3, to ∼75% at redshift 1.3.

Original languageEnglish (US)
Pages (from-to)473-479
Number of pages7
JournalAstronomical Journal
Volume109
Issue number2
DOIs
StatePublished - Feb 1995

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quasars
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All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Schmidt, Maarten ; Van Gorkom, J. H. ; Schneider, Donald P. ; Gunn, James E. / Differential evolution of radio quiet and radio loud quasars. In: Astronomical Journal. 1995 ; Vol. 109, No. 2. pp. 473-479.
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Differential evolution of radio quiet and radio loud quasars. / Schmidt, Maarten; Van Gorkom, J. H.; Schneider, Donald P.; Gunn, James E.

In: Astronomical Journal, Vol. 109, No. 2, 02.1995, p. 473-479.

Research output: Contribution to journalArticle

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AU - Schneider, Donald P.

AU - Gunn, James E.

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