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dc.contributor.authorHickox, Ryan C.
dc.contributor.authorMyers, Adam D.
dc.contributor.authorGreene, Jenny E.
dc.contributor.authorHainline, Kevin N.
dc.contributor.authorZakamska, Nadia
dc.contributor.authorDiPompeo, Michael A.
dc.date.accessioned2017-11-14T23:54:42Z
dc.date.available2017-11-14T23:54:42Z
dc.date.issued2017-10-30
dc.identifier.citationComposite Spectral Energy Distributions and Infrared–Optical Colors of Type 1 and Type 2 Quasars 2017, 849 (1):53 The Astrophysical Journalen
dc.identifier.issn1538-4357
dc.identifier.doi10.3847/1538-4357/aa8c77
dc.identifier.urihttp://hdl.handle.net/10150/626048
dc.description.abstractWe present observed mid-infrared and optical colors and composite spectral energy distributions (SEDs) of type 1 (broad-line) and 2 (narrow-line) quasars selected from Sloan Digital Sky Survey (SDSS) spectroscopy. A significant fraction of powerful quasars are obscured by dust and are difficult to detect in optical photometric or spectroscopic surveys. However, these may be more easily identified on the basis of mid-infrared (MIR) colors and SEDs. Using samples of SDSS type 1 and 2 matched in redshift and [O III] luminosity, we produce composite rest-frame 0.2-15 mu m SEDs based on SDSS, UKIDSS, and Wide-field Infrared Survey Explorer photometry and perform model fits using simple galaxy and quasar SED templates. The SEDs of type 1 and 2 quasars are remarkably similar, with the differences explained primarily by the extinction of the quasar component in the type 2 systems. For both types of quasar, the flux of the active galactic nucleus (AGN) relative to the host galaxy increases with AGN luminosity (L-[O III]) and redder observed MIR color, but we find only weak dependencies of the composite SEDs on mechanical jet power as determined through radio luminosity. We conclude that luminous quasars can be effectively selected using simple MIR color criteria similar to those identified previously (W1-W2 > 0.7; Vega), although these criteria miss many heavily obscured objects. Obscured quasars can be further identified based on optical-IR colors (for example, (u-W3[AB])> 1.4(W1-W2[Vega])+ 3.2). These results illustrate the power of large statistical studies of obscured quasars selected on the basis of MIR and optical photometry.
dc.description.sponsorshipNational Science Foundation through AST [1211112, 1515404]; CAREER [1554584]; NASA [NNX16AN48G, NNX15AU32H, NNX12AE38G, NNX15AP24G]; Alfred P. Sloan Research Fellowship; National Aeronautics and Space Administration; National Science Foundation; Alfred P. Sloan Foundation; U.S. Department of Energy Office of Scienceen
dc.language.isoenen
dc.publisherIOP PUBLISHING LTDen
dc.relation.urlhttp://stacks.iop.org/0004-637X/849/i=1/a=53?key=crossref.b4e01b6af0cb821ced101f2e40f0220den
dc.rights© 2017. The American Astronomical Society. All rights reserved.en
dc.subjectgalaxies: activeen
dc.subjectinfrared: galaxiesen
dc.subjectquasars: generalen
dc.subjectsurveysen
dc.titleComposite Spectral Energy Distributions and Infrared–Optical Colors of Type 1 and Type 2 Quasarsen
dc.typeArticleen
dc.contributor.departmentUniv Arizona, Steward Observen
dc.identifier.journalThe Astrophysical Journalen
dc.description.collectioninformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.en
dc.eprint.versionFinal published versionen
refterms.dateFOA2018-06-24T01:58:16Z
html.description.abstractWe present observed mid-infrared and optical colors and composite spectral energy distributions (SEDs) of type 1 (broad-line) and 2 (narrow-line) quasars selected from Sloan Digital Sky Survey (SDSS) spectroscopy. A significant fraction of powerful quasars are obscured by dust and are difficult to detect in optical photometric or spectroscopic surveys. However, these may be more easily identified on the basis of mid-infrared (MIR) colors and SEDs. Using samples of SDSS type 1 and 2 matched in redshift and [O III] luminosity, we produce composite rest-frame 0.2-15 mu m SEDs based on SDSS, UKIDSS, and Wide-field Infrared Survey Explorer photometry and perform model fits using simple galaxy and quasar SED templates. The SEDs of type 1 and 2 quasars are remarkably similar, with the differences explained primarily by the extinction of the quasar component in the type 2 systems. For both types of quasar, the flux of the active galactic nucleus (AGN) relative to the host galaxy increases with AGN luminosity (L-[O III]) and redder observed MIR color, but we find only weak dependencies of the composite SEDs on mechanical jet power as determined through radio luminosity. We conclude that luminous quasars can be effectively selected using simple MIR color criteria similar to those identified previously (W1-W2 > 0.7; Vega), although these criteria miss many heavily obscured objects. Obscured quasars can be further identified based on optical-IR colors (for example, (u-W3[AB])> 1.4(W1-W2[Vega])+ 3.2). These results illustrate the power of large statistical studies of obscured quasars selected on the basis of MIR and optical photometry.


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