DUSTY QUASARS AT HIGH REDSHIFTS

ABSTRACT A population of quasars at z ∼ 2 is determined based on dust luminosities L (7.8 m) that includes unobscured, partially obscured, and obscured quasars. Quasars are classified by the ratio L (0.25 m)/ L (7.8 m) = UV/IR, assumed to measure obscuration of UV luminosity by the dust that produce...

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Bibliographic Details
Published in:The Astrophysical journal 2016-09, Vol.828 (1), p.43-43
Main Authors: Weedman, Daniel, Sargsyan, Lusine
Format: Article
Language:English
Subjects:
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
COSMIC DUST
DENSITY
DETECTION
Dust
ENERGY SPECTRA
GALAXIES
galaxies: active
galaxies: evolution
galaxies: high-redshift
galaxies: starburst
GALAXY NUCLEI
Infrared
infrared: galaxies
LUMINOSITY
PHOTOMETRY
QUASARS
quasars: general
RED SHIFT
Sky surveys (astronomy)
SPACE
Spires
STAR EVOLUTION
WAVELENGTHS
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Summary:ABSTRACT A population of quasars at z ∼ 2 is determined based on dust luminosities L (7.8 m) that includes unobscured, partially obscured, and obscured quasars. Quasars are classified by the ratio L (0.25 m)/ L (7.8 m) = UV/IR, assumed to measure obscuration of UV luminosity by the dust that produces IR luminosity. Quasar counts at rest-frame 7.8 m are determined for quasars in the Boötes field of the NOAO Deep Wide Field Survey using 24 m sources with optical redshifts from the AGN and Galaxy Evolution Survey (AGES) or infrared redshifts from the Spitzer Infrared Spectrograph. Spectral energy distributions are extended to far-infrared wavelengths using observations from the Herschel Space Observatory Spectral and Photometric Imaging Receiver (SPIRE), and new SPIRE photometry is presented for 77 high-redshift quasars from the Sloan Digital Sky Survey. It is found that unobscured and obscured quasars have similar space densities at rest-frame 7.8 m, but the ratio L (100 m)/L (7.8 m) is about three times higher for obscured quasars than for unobscured, so that far-infrared or submillimeter quasar detections are dominated by obscured quasars. We find that only ∼5% of high-redshift submillimeter sources are quasars and that existing 850 m surveys or 2 mm surveys should already have detected sources at z ∼ 10 if quasar and starburst luminosity functions remain the same from z = 2 until z = 10.
ISSN:0004-637X
1538-4357
DOI:10.3847/0004-637X/828/1/43