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dc.contributor.authorRivera, AB
dc.contributor.authorRichards, GT
dc.contributor.authorGallagher, SC
dc.contributor.authorMcCaffrey, TV
dc.contributor.authorRankine, AL
dc.contributor.authorHewett, Paul
dc.contributor.authorShemmer, O
dc.date.accessioned2022-06-07T08:16:38Z
dc.date.available2022-06-07T08:16:38Z
dc.date.issued2022-06-01
dc.date.submitted2021-09-24
dc.identifier.issn0004-637X
dc.identifier.otherapjac6a5d
dc.identifier.otherac6a5d
dc.identifier.otheraas34985
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/337834
dc.description.abstract<jats:title>Abstract</jats:title> <jats:p>We examine the UV/X-ray properties of 1378 quasars in order to link empirical correlations to theoretical models of the physical mechanisms dominating quasars as a function of mass and accretion rate. The clarity of these correlations is improved when (1) using C <jats:sc>iv</jats:sc> broad emission line equivalent width (EQW) and blueshift (relative to systemic) values calculated from high signal-to-noise ratio reconstructions of optical/UV spectra and (2) removing quasars expected to be absorbed based on their UV/X-ray spectral slopes. In addition to using the traditional C <jats:sc>iv</jats:sc> parameter space measures of C <jats:sc>iv</jats:sc> EQW and blueshift, we define a “C <jats:sc>iv</jats:sc> ∥ distance” along a best-fit polynomial curve that incorporates information from both C <jats:sc>iv</jats:sc> parameters. We find that the C <jats:sc>iv</jats:sc> ∥ distance is linearly correlated with both the optical-to-X-ray slope, <jats:italic>α</jats:italic> <jats:sub>ox</jats:sub>, and broad-line He <jats:sc>ii</jats:sc> EQW, which are known spectral energy distribution indicators, but does not require X-ray or high spectral resolution UV observations to compute. The C <jats:sc>iv</jats:sc> ∥ distance may be a better indicator of the mass-weighted accretion rate, parameterized by <jats:italic>L</jats:italic>/<jats:italic>L</jats:italic> <jats:sub>Edd</jats:sub>, than the C <jats:sc>iv</jats:sc> EQW or blueshift alone, as those relationships are known to break down at the extrema. Conversely, there is only a weak correlation with the X-ray energy index (Γ), an alternate <jats:italic>L</jats:italic>/<jats:italic>L</jats:italic> <jats:sub>Edd</jats:sub> indicator. We find no X-ray or optical trends in the direction perpendicular to the C <jats:sc>iv</jats:sc> distance that could be used to reveal differences in accretion disk, wind, or corona structure that could be widening the C <jats:sc>iv</jats:sc> EQW–blueshift distribution. A different parameter (such as metallicity) not traced by these data must come into play.</jats:p>
dc.languageen
dc.publisherAmerican Astronomical Society
dc.subject310
dc.subjectGalaxies and Cosmology
dc.titleExploring Changes in Quasar Spectral Energy Distributions across C iv Parameter Space
dc.typeArticle
dc.date.updated2022-06-07T08:16:37Z
prism.issueIdentifier2
prism.publicationNameAstrophysical Journal
prism.volume931
dc.identifier.doi10.17863/CAM.85243
dcterms.dateAccepted2022-04-20
rioxxterms.versionofrecord10.3847/1538-4357/ac6a5d
rioxxterms.versionVoR
rioxxterms.licenseref.urihttp://creativecommons.org/licenses/by/4.0/
dc.contributor.orcidRivera, AB [0000-0001-8125-1669]
dc.contributor.orcidRichards, GT [0000-0002-1061-1804]
dc.contributor.orcidGallagher, SC [0000-0001-6217-8101]
dc.contributor.orcidMcCaffrey, TV [0000-0002-9321-9559]
dc.contributor.orcidRankine, AL [0000-0002-2091-1966]
dc.contributor.orcidHewett, Paul [0000-0002-6528-1937]
dc.contributor.orcidShemmer, O [0000-0003-4327-1460]
dc.identifier.eissn1538-4357
pubs.funder-project-idNational Aeronautics and Space Administration (NASA) (NAS5- 26555)
pubs.funder-project-idNational Aeronautics and Space Administration (NASA) (G07-18110X)
pubs.funder-project-idNSF ∣ National Science Board (NSB) (1908716)
cam.issuedOnline2022-06-06


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