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Broad-Band Spectroscopy of Hercules X-1 with SuzakuHercules X-1 was observed with Suzaku in the main-on state from 2005 to 2010. The 0.4- 100 keV wide-band spectra obtained in four observations showed a broad hump around 4-9 keV in addition to narrow Fe lines at 6.4 and 6.7 keV. The hump was seen in all the four observations regardless of the selection of the continuum models. Thus it is considered a stable and intrinsic spectral feature in Her X-1. The broad hump lacked a sharp structure like an absorption edge. Thus it was represented by two different spectral models: an ionized partial covering or an additional broad line at 6.5 keV. The former required a persistently existing ionized absorber, whose origin was unclear. In the latter case, the Gaussian fitting of the 6.5-keV line needs a large width of sigma = 1.0-1.5 keV and a large equivalent width of 400-900 eV. If the broad line originates from Fe fluorescence of accreting matter, its large width may be explained by the Doppler broadening in the accretion flow. However, the large equivalent width may be inconsistent with a simple accretion geometry.
Document ID
20150008976
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Asami, Fumi (Nishina Center for Accelerator-Based Science Wako, Japan)
Enoto, Teruaki (Nishina Center for Accelerator-Based Science Wako, Japan)
Iwakiri, Wataru (Nishina Center for Accelerator-Based Science Wako, Japan)
Yamada, Shin'ya (Nishina Center for Accelerator-Based Science Wako, Japan)
Tamagawa, Toru (Nishina Center for Accelerator-Based Science Wako, Japan)
Mihara, Tatehiro (Nishina Center for Accelerator-Based Science Wako, Japan)
Nagase, Fumiaki (Japan Aerospace Exploration Agency Tokyo, Japan)
Date Acquired
May 28, 2015
Publication Date
May 20, 2014
Publication Information
Publication: Publications of the Astronomical Society of Japan
Volume: 66
Issue: 2
Subject Category
Astrophysics
Report/Patent Number
GSFC-E-DAA-TN21608
Distribution Limits
Public
Copyright
Other
Keywords
X-rays: stars
binaries: spectroscopic
pulsars