Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/4029
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dc.contributor.authorVasiliev, Evgenii O.-
dc.contributor.authorSethi, S.K.-
dc.contributor.authorNath, Biman B.-
dc.date.accessioned2011-04-08T09:10:45Z-
dc.date.available2011-04-08T09:10:45Z-
dc.date.issued2010-07-28-
dc.identifier.citationAstrophysical Journal, 2010, Vol. 719, p1343en
dc.identifier.issn1538-4357-(Online)-
dc.identifier.issn0004-637X-
dc.identifier.urihttp://hdl.handle.net/2289/4029-
dc.descriptionRestricted Access. An open-access version is available at arXiv.org (one of the alternative locations)en
dc.description.abstractWe constrain the spectrum of the cosmic ultraviolet background radiation by fitting the observed abundance ratios of carbon ions at z ~ 2-3 with those expected from different models of the background radiation. We use the recently calculated modulation of the background radiation between 3 and 4 Ryd due to resonant line absorption by intergalactic He II and determine the ratios of C III to C IV expected at these redshifts, as functions of metallicity, gas density, and temperature. Our analysis of the observed ratios shows that "delayed reionization" models, which assume a large fraction of He II at z ~ 3, are not favored by data. Our results suggest that He II reionization was inhomogeneous, consistent with the predictions from recent simulations.en
dc.language.isoenen
dc.publisherIOP Publishing Ltd.en
dc.relation.urihttp://adsabs.harvard.edu/abs/2010ApJ...719.1343Ven
dc.relation.urihttp://arxiv.org/abs/1006.4985en
dc.relation.urihttp://dx.doi.org/10.1088/0004-637X/719/2/1343en
dc.rights2010 IOP Publishing for the American Astronomical Societyen
dc.subjectcosmology: theoryen
dc.subjectdiffuse radiationen
dc.subjectintergalactic mediumen
dc.subjectquasars: generalen
dc.titleCarbon ionization states and the cosmic far-UV background with He II absorptionen
dc.typeArticleen
Appears in Collections:Research Papers (A&A)

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