JAXA Repository / AIREX 未来へ続く、宙(そら)への英知
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titleFe K emission lines in neutron star low-mass X-ray binaries
Author(eng)Cackett, M. Edward; Miller, J. M.; Ballantyne, D. R.; Barret, D.; Bhattacharyya, S.; Boutelier, M.; Miller, M. C.; Strohmayer, T. E.; Wijnands, R.
Author Affiliation(eng)Department of Astronomy, University of Michigan; Department of Astronomy, University of Michigan; Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology; CESR, CNRS/UPS; Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research; CESR, CNRS/UPS; Department of Astronomy, University of Maryland; Astrophysics Science Division, NASA/GSFC; Astronomical Institute, University of Amsterdam
Issue Date2010-02-26
Japan Aerospace Exploration Agency (JAXA)
Publication title宇宙航空研究開発機構特別資料:
JAXA Special Publication: The Energetic Cosmos; from Suzaku to ASTRO-H
Start page248
End page251
Publication date2010-02-26
AbstractOver recent years, Suzaku and XMM-Newton observations of neutron star low-mass X-ray binaries have uncovered broad, asymmetric Fe K emission lines in these sources. It is believed that the lines arise from irradiation of the innermost accretion disk. Thus, the line profile is skewed by relativistic effects present there, leading to a measure of the inner disk radius. We summarize our comprehensive analysis of the spectra from 10 neutron star low-mass X-ray binaries here. We not only fit simple phenomenological models to the spectra, but also a more self-consistent approach using a reflection model wherein a blackbody provides the irradiating flux. Such a model is appropriate for these sources where a blackbody dominates the spectrum from around 8 - 20 keV. A realistic geometry for this reflection would involve the boundary layer (the assumed source of blackbody-like emission) irradiating the inner disk. From our modeling, we only find a small range in inner disk radius (6 - 15 GM/c(exp 2) in the majority of cases), and find no obvious trend with luminosity. One particularly interesting source is the accreting millisecond X-ray pulsar SAX J1808.4-3658. The Fe K emission line in this source allows us to estimate the magnetic field strength in this system to be approximately 3 x 10(exp 8) G, broadly consistent with previous independent estimates.
DescriptionMeeting Information: The 3rd Suzaku international Conference "Energetic Cosmos : from Suzaku to ASTRO-H" (June 29-July 2, 2009. Grand Park Otaru Hotel), Otaru, Hokkaido Japan
Meeting sponsors: The University of Tokyo, The Institute of Physical and Chemical Research, The Japan Society for the Promotion of Science
KeywordsX-rays: binaries - stars: neutron - accretion, accretion disks
Document TypeConference Paper
JAXA Category特別資料
Report NoJAXA-SP-09-008E

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