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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 308598.0, MPI für Astronomie / Publikationen_mpia
Spectral energy distributions and multiwavelength selection of type 1 quasars
Authors:Richards, G. T.; Lacy, M.; Storrie-Lombardi, L. J.; Hall, P. B.; Gallagher, S. C.; Hines, D. C.; Fan, X.; Papovich, C.; Vanden Berk, D. E.; Trammell, G. B.; Schneider, D. P.; Vestergaard, M.; York, D. G.; Jester, S.; Anderson, S. F.; Budavári, T.; Szalay, A. S.
Date of Publication (YYYY-MM-DD):2006
Journal Abbrev.:Astrophysical Journal Supplement Series
Start Page:470
End Page:497
Audience:Not Specified
Abstract / Description:We present an analysis of the mid-infrared (MIR) and optical properties of type 1 (broad-line) quasars detected by the Spitzer Space Telescope. The MIR color-redshift relation is characterized to z~3, with predictions to z=7. We demonstrate how combining MIR and optical colors can yield even more efficient selection of active galactic nuclei (AGNs) than MIR or optical colors alone. Composite spectral energy distributions (SEDs) are constructed for 259 quasars with both Sloan Digital Sky Survey and Spitzer photometry, supplemented by near-IR, GALEX, VLA, and ROSAT data, where available. We discuss how the spectral diversity of quasars influences the determination of bolometric luminosities and accretion rates; assuming the mean SED can lead to errors as large as 50% for individual quasars when inferring a bolometric luminosity from an optical luminosity. Finally, we show that careful consideration of the shape of the mean quasar SED and its redshift dependence leads to a lower estimate of the fraction of reddened/obscured AGNs missed by optical surveys as compared to estimates derived from a single mean MIR to optical flux ratio.
Free Keywords:Catalogs; Galaxies: Active; Infrared: Galaxies; Galaxies: Quasars: General; Radio Continuum: Galaxies; Surveys; Ultraviolet: Galaxies; X-Rays: Galaxies
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
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