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Show simple item record Yao, Y. Tripp, T. M. Wang, Q. D. Danforth, Charles W. Canizares, Claude R. Shull, J. M. Marshall, Herman Lee Song, L. 2010-02-11T16:29:13Z 2010-02-11T16:29:13Z 2009-05 2008-12
dc.identifier.issn 0004-637X
dc.description.abstract The observed intergalactic O vi absorbers at z > 0 have been regarded as a significant reservoir of the “missing baryons.” However, to fully understand how these absorbers contribute to the baryon inventory, it is crucial to determine whether the systems are collisionally ionized or photoionized (or both). Using the identified intergalactic Ovi absorbers as tracers, we search for the corresponding X-ray absorption lines, which are useful for finding the missing baryons and for revealing the nature of the O vi absorbers. Stacking the Chandra grating spectra along six AGN sight lines, we obtain three spectra with signal-to-noise ratios of 32, 28, and 10 per 12.5 mÅ spectral bin around the expected O vii Kα wavelength. These spectra correspond to O vi absorbers with various dynamic properties. We find no detectable Ne ix, O vii, O viii, N vii, or C vi absorption lines in the spectra, but the high counting statistics allows us to obtain firm upper limits on the corresponding ionic column densities (in particular NO vii < 10N [subscript Ovi] on average at the 95% confidence level). Jointly analyzing these nondetected Xray lines with the averaged O vi column density, we further limit the average temperature of the Ovi-bearing gas to be T < 10 [superscript 5.7] K in collisional ionization equilibrium. We discuss the implications of these results for physical properties of the putative warm–hot intergalactic medium and its detection in future X-ray observations. en
dc.description.sponsorship Smithsonian Astrophysical Observatory en
dc.description.sponsorship NASA en
dc.description.sponsorship Chandra en
dc.language.iso en_US
dc.publisher American Astronomical Society en
dc.relation.isversionof en
dc.rights Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. en
dc.source Claude Canizares via Gail Monahan en
dc.type Article en
dc.identifier.citation X-raying the Intergalactic O VI Absorbers Y. Yao, T. M. Tripp, Q. D. Wang, C. W. Danforth, C. R. Canizares, J. M. Shull, H. L. Marshall, and L. Song 2009 ApJ 697 1784-1792 doi: 10.1088/0004-637X/697/2/1784 (C)2009 The American Astronomical Society. en
dc.contributor.department Kavli Institute for Astrophysics and Space Research en_US
dc.contributor.approver Canizares, Claude R.
dc.contributor.mitauthor Canizares, Claude R.
dc.contributor.mitauthor Marshall, Herman Lee
dc.relation.journal Astrophysical Journal en
dc.identifier.mitlicense PUBLISHER_POLICY en
dc.eprint.version Final published version en
dc.type.uri en
eprint.status en
eprint.grantNumber NNX08AJ44G en
eprint.grantNumber SV3-73016 en
eprint.grantNumber NNX08AC14G en
eprint.grantNumber AR7-8014 en
dspace.orderedauthors Yao, Y.; Tripp, T. M.; Wang, Q. D.; Danforth, C. W.; Canizares, C. R.; Shull, J. M.; Marshall, H. L.; Song, L. en

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