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dc.contributor.authorBañados, Eduardo
dc.contributor.authorConnor, Thomas
dc.contributor.authorStern, Daniel
dc.contributor.authorMulchaey, John
dc.contributor.authorFan, Xiaohui
dc.contributor.authorDecarli, R.
dc.contributor.authorFarina, Emanuele P.
dc.contributor.authorMazzucchelli, C.
dc.contributor.authorVenemans, B. P.
dc.contributor.authorWalter, Fabian
dc.contributor.authorWang, Feige
dc.contributor.authorYang, Jinyi
dc.date.accessioned2018-05-01T23:26:07Z
dc.date.available2018-05-01T23:26:07Z
dc.date.issued2018-03-27
dc.identifier.citationEduardo Bañados et al 2018 ApJL 856 L25en_US
dc.identifier.issn2041-8213
dc.identifier.doi10.3847/2041-8213/aab61e
dc.identifier.urihttp://hdl.handle.net/10150/627539
dc.description.abstractWe present a 45 ks Chandra observation of the quasar ULAS J1342+0928 at z=7.54. We detect 14.0(-3.7)(+4.8) counts from the quasar in the observed-frame energy range 0.5-7.0 keV (6 sigma detection), representing the most distant non-transient astronomical source identified in X-rays to date. The present data are sufficient only to infer rough constraints on the spectral parameters. We find an X-ray hardness ratio of HR = -0.51(-0.28)(+0.26) between the 0.5-2.0 keV and 2.0-7.0 keV ranges and derive a power-law photon index of Gamma= 1.95(-0.53)(+0.55). Assuming a typical value for high-redshift quasars of Gamma = 1.9, ULAS J1342+0928 has a 2-10 keV rest-frame X-ray luminosity of L2-10 = 11.6(-3.5)(+4.3) x 10(44) erg s(-1). Its X-ray-to-optical power-law slope is alpha(OX) = -1.67(-0.10)(+0.16), consistent with the general trend indicating that the X-ray emission in the most bolometrically powerful quasars is weaker relative to their optical emission.en_US
dc.description.sponsorshipERCen_US
dc.language.isoenen_US
dc.publisherIOP PUBLISHING LTDen_US
dc.relation.urlhttp://stacks.iop.org/2041-8205/856/i=2/a=L25?key=crossref.c101bca1f8631b517583400166e8265cen_US
dc.rights© 2018. The American Astronomical Society. All rights reserved.en_US
dc.subjectcosmology: observationsen_US
dc.subjectearly universeen_US
dc.subjectquasars: individual (ULAS J134208.10+092838.61)en_US
dc.titleX-Rays from the Redshift 7.54 Quasar ULAS J1342+0928en_US
dc.typeArticleen_US
dc.contributor.departmentUniv Arizona, Steward Observen_US
dc.identifier.journalASTROPHYSICAL JOURNAL LETTERSen_US
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_US
dc.eprint.versionFinal published versionen_US
dc.source.journaltitleThe Astrophysical Journal
dc.source.volume856
dc.source.issue2
dc.source.beginpageL25
refterms.dateFOA2018-05-01T23:26:08Z


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