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dc.contributor.authorHaiman, Zoltan
dc.contributor.authorLoeb, Abraham
dc.date.accessioned2019-09-24T12:04:10Z
dc.date.issued1999
dc.identifier.citationHaiman, Zoltan, and Abraham Loeb. 1999. “X-Ray Emission from the First Quasars.” The Astrophysical Journal 521 (1): L9–12. https://doi.org/10.1086/312177.
dc.identifier.issn0004-637X
dc.identifier.issn1538-4357
dc.identifier.urihttp://nrs.harvard.edu/urn-3:HUL.InstRepos:41393256*
dc.description.abstractIt is currently unknown whether the universe was reionized by quasars or stars at z greater than or similar to 5. We point out that quasars can be best distinguished from stellar systems by their X-ray emission. Based on a simple hierarchical CDM model, we predict the number counts and X-ray fluxes of quasars at high redshifts. The model is consistent with available data on the luminosity function of high-redshift quasars in the optical and soft X-ray bands. The cumulative contribution of faint, undetected quasars in our model is consistent with the unresolved fraction of the X-ray background. We find that the Chandra X-ray Observatory might detect similar to 10(2) quasars from redshifts z greater than or similar to 5 per its 17' x 17' field of view at the flux threshold of similar to 2 x 10(-16) ergs s(-1) cm(-2). The redshifts of these faint point sources could be identified by follow-up infrared observations from the ground or with the Next Generation Space Telescope.
dc.language.isoen_US
dc.publisherAmerican Astronomical Society
dash.licenseLAA
dc.titleX-Ray Emission from the First Quasars
dc.typeJournal Article
dc.description.versionVersion of Record
dc.relation.journalThe Astrophysical Journal
dash.depositing.authorLoeb, Abraham::9975df1f269ab49c1ad5a328a1ec1476::600
dc.date.available2019-09-24T12:04:10Z
dash.workflow.comments1Science Serial ID 95681
dc.identifier.doi10.1086/312177
dash.source.volume521;1
dash.source.pageL9-L12


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