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dc.contributor.authorSchulz, Norbert S.
dc.contributor.authorNowak, Michael A.
dc.contributor.authorChakrabarty, Deepto
dc.contributor.authorCanizares, Claude R.
dc.date.accessioned2012-08-07T15:28:23Z
dc.date.available2012-08-07T15:28:23Z
dc.date.issued2010-12
dc.date.submitted2010-05
dc.identifier.issn1538-4357
dc.identifier.issn0004-637X
dc.identifier.urihttp://hdl.handle.net/1721.1/72014
dc.description.abstractWe observed the ultra-compact binary candidate 4U 0614+091 for a total of 200 ks with the high-energy transmission gratings on board the Chandra X-ray Observatory. The source is found at various intensity levels with spectral variations present. X-ray luminosities vary between 2.0 × 10[superscript 36] erg s–1 and 3.5 × 10[superscript 36] erg s[superscript –1]. Continuum variations are present at all times and spectra can be fit well with a power-law component, a high kT blackbody component, and a broad line component near oxygen. The spectra require adjustments to the Ne K edge and in some occasions also to the Mg K edge. Once further resolved, the Ne K edge region appears variable in terms of optical depths and morphology. The edge vicinity reveals an average velocity smear of ~3500 km s[superscript –1] implying a characteristic radius of the order of <10[superscript 9] cm consistent with an ultra-compact binary nature. The variability proves that the excess is intrinsic to the source. The data seem to indicate excess column densities of up to several 10[superscript 18] cm[superscript –2]. However, there are some serious problems with an Ne I interpretation in ultra-compact disks and we need to consider alternative interpretations, which include a variable O VIII ionization edge, as likely candidates. We test such possibilities with existing observations. The prominent soft emission line complex near the O VIII Lyα position appears extremely broad and relativistic effects from near the innermost disk have to be included. Gravitationally broadened line fits also provide nearly edge-on angles of inclination consistent with the observed high dynamics near the Ne K edge. The emissions appear consistent with an ionized disk with ionization parameters of the order of 10[superscript 4] at radii of a few 10[superscript 7] cm. The line wavelengths with respect to O VIII Lyα are found variably blueshifted indicating more complex inner disk dynamics.en_US
dc.language.isoen_US
dc.publisherIOP Publishingen_US
dc.relation.isversionofhttp://dx.doi.org/10.1088/0004-637X/725/2/2417en_US
dc.rightsCreative Commons Attribution-Noncommercial-Share Alike 3.0en_US
dc.rights.urihttp://creativecommons.org/licenses/by-nc-sa/3.0/en_US
dc.sourceProf. Canizares via Mat Willmotten_US
dc.titleDynamical K edge and line variations in the X-ray spectrum of the ultra-compact binary 4U 0614+091en_US
dc.typeArticleen_US
dc.identifier.citationSchulz, N. S. et al. “Dynamical K edge and line variations in the X-ray spectrum of the ultra-compact binary 4U 0614+091.” The Astrophysical Journal 725.2 (2010): 2417-2425. Web. 7 Aug. 2012.en_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Physicsen_US
dc.contributor.departmentMIT Kavli Institute for Astrophysics and Space Researchen_US
dc.contributor.approverCanizares, Claude R.
dc.contributor.mitauthorSchulz, Norbert S.
dc.contributor.mitauthorNowak, Michael A.
dc.contributor.mitauthorChakrabarty, Deepto
dc.contributor.mitauthorCanizares, Claude R.
dc.relation.journalAstrophysical Journalen_US
dc.eprint.versionAuthor's final manuscripten_US
dc.type.urihttp://purl.org/eprint/type/JournalArticleen_US
eprint.statushttp://purl.org/eprint/status/PeerRevieweden_US
dspace.orderedauthorsSchulz, N. S.; Nowak, M. A.; Chakrabarty, D.; Canizares, C. R.en
dc.identifier.orcidhttps://orcid.org/0000-0001-8804-8946
dc.identifier.orcidhttps://orcid.org/0000-0002-5769-8441
mit.licenseOPEN_ACCESS_POLICYen_US


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