Composite Spectra from the FIRST Bright Quasar Survey
Autor: | Michael D. Gregg, Robert H. Becker, Sally A. Laurent-Muehleisen, Michael S. Brotherton, Hien D. Tran, Richard L. White |
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Jazyk: | angličtina |
Rok vydání: | 2000 |
Předmět: |
Physics
Absorption spectroscopy Astrophysics::High Energy Astrophysical Phenomena Astrophysics (astro-ph) Composite number FOS: Physical sciences Astronomy and Astrophysics Quasar Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Spectral line Wavelength Space and Planetary Science Angstrom Absorption (electromagnetic radiation) Astrophysics::Galaxy Astrophysics |
Popis: | We present a very high signal-to-noise ratio composite spectrum created using 657 radio-selected quasars from the FIRST Bright Quasar Survey. The spectrum spans rest-frame wavelengths 900 - 7500 Angstroms. Additionally we present composite spectra formed from subsets of the total data set in order to investigate the spectral dependence on radio loudness and the presence of broad absorption. In particular, radio-loud quasars are red compared to radio-quiet quasars, and quasars showing low-ionization broad absorption lines are red compared to other quasars. We compare our composites with those from the Large Bright Quasar Survey. Composite quasar spectra have proven to be valuable tools for a host of applications, and in that spirit we make these publically available via the FIRST survey web page. To appear in ApJ. 15 pages, 8 figures |
Databáze: | OpenAIRE |
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