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The Optical/Near-IR Colours of Red Quasars

Francis, Paul; Whiting, Matthew T; Webster, Rachel L

Description

We present quasi-simultaneous multi-colour optical/near-IR photometry for 157 radio selected quasars, forming an unbiassed sub-sample of the Parkes Flat-Spectrum Sample. Data are also presented for 12 optically selected QSOs, drawn from the Large Bright QSO Survey. The spectral energy distributions of the radio- and optically-selected sources are quite different. The optically selected QSOs are all very similar: they have blue spectral energy distributions curving downwards at shorter...[Show more]

dc.contributor.authorFrancis, Paul
dc.contributor.authorWhiting, Matthew T
dc.contributor.authorWebster, Rachel L
dc.date.accessioned2015-12-13T23:16:35Z
dc.date.available2015-12-13T23:16:35Z
dc.identifier.issn1323-3580
dc.identifier.urihttp://hdl.handle.net/1885/89487
dc.description.abstractWe present quasi-simultaneous multi-colour optical/near-IR photometry for 157 radio selected quasars, forming an unbiassed sub-sample of the Parkes Flat-Spectrum Sample. Data are also presented for 12 optically selected QSOs, drawn from the Large Bright QSO Survey. The spectral energy distributions of the radio- and optically-selected sources are quite different. The optically selected QSOs are all very similar: they have blue spectral energy distributions curving downwards at shorter wavelengths. Roughly 90% of the radio-selected quasars have roughly power-law spectral energy distributions, with slopes ranging from Fν ∝ ν0 to Fν, ∝ ν-2. The remaining 10% have spectral energy distributions showing sharp peaks: these are radio galaxies and highly reddened quasars. Four radio sources were not detected down to magnitude limits of H ∼ 19 · 6. These are probably high redshift (z > 3) galaxies or quasars. We show that the colours of our red quasars lie close to the stellar locus in the optical: they will be hard to identify in surveys such as the Sloan Digital Sky Survey. If near-IR photometry is added, however, the red power-law sources can be clearly separated from the stellar locus: IR surveys such as 2MASS should be capable of finding these sources on the basis of their excess flux in the K-band.
dc.publisherCSLI Publications
dc.rightshttp://www.sherpa.ac.uk/romeo/issn/1323-3580/..."Author's post-print on departmental website, institutional repository, non-commercial subject-based repositories, such as PubMed Central, Europe PMC or arXiv, after a 6 months embargo" from SHERPA/RoMEO site (as at 13/09/18)
dc.sourcePublications of the Astronomical Society of Australia
dc.subjectKeywords: Methods: observational; Quasars: general
dc.titleThe Optical/Near-IR Colours of Red Quasars
dc.typeJournal article
local.description.notesImported from ARIES
local.description.refereedYes
local.identifier.citationvolume53
dc.date.issued2000
local.identifier.absfor020103 - Cosmology and Extragalactic Astronomy
local.identifier.ariespublicationMigratedxPub19532
local.type.statusAccepted Version
local.contributor.affiliationFrancis, Paul, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationWhiting, Matthew T, University of New South Wales
local.contributor.affiliationWebster, Rachel L, University of Melbourne
local.bibliographicCitation.startpage56
local.bibliographicCitation.lastpage71
local.identifier.doi10.1071/AS00056
dc.date.updated2015-12-12T08:48:46Z
local.identifier.scopusID2-s2.0-0034383196
dcterms.accessRightsOpen Access
CollectionsANU Research Publications

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