The ultraviolet spectra of radio-loud and radio-quiet quasars

Paul J. Francis, Eric J. Hooper, Chris D. Impey

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61 Scopus citations


The rest-frame ultraviolet spectral properties of matched samples of radio-loud, radio-moderate, and radio-quiet quasars are investigated, using quasars drawn from the Large Bright QSO Survey. We confirm the absence of spectral differences between radio-loud and radio-quiet quasars at rest-frame wavelengths longward of 1600 Å, as reported by previous authors. However, at shorter wavelengths we find a significant difference: radio-loud quasars have narrower (96% confidence), higher equivalent width (97% confidence) Lyman-α and C IV emission lines. We further investigate quasars which are radio quiet, but have radio-to-optical flux ratios at the upper extreme of the radio-quiet population. Broad absorption line quasars are overabundant by a factor of ∼10 in this radio-moderate population; the overabundance is significant at a 99.99% confidence level.

Original languageEnglish (US)
Pages (from-to)417-425
Number of pages9
JournalAstronomical Journal
Issue number2
StatePublished - Aug 1993

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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