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The Microquasar Cyg X-1: A Short ReviewWe review the spectral properties of the black hole candidate Cygnus X-I. Specifically, we discuss two recent sets of multi-satellite observations. One comprises a 0.5-500 keY spectrum, obtained with eve!)' flying X-ray satellite at that time, that is among the hardest Cyg X-I spectra observed to date. The second set is comprised of 0.5-40 keV Chandra-HETG plus RXTE-PCA spectra from a radio-quiet, spectrally soft state. We first discuss the "messy astrophysics" often neglected in the study of Cyg X-I, i.e., ionized absorption from the wind of the secondary and the foreground dust scattering halo. We then discuss components common to both state extremes: a low temperature accretion disk, and a relativistically broadened Fe line and reflection. Hard state spectral models indicate that the disk inner edge does not extend beyond > or approx.= 40 GM/sq c , and may even approach as close as approx. = 6GM/sq c. The soft state exhibits a much more prominent disk component; however, its very low normalization plausibly indicates a spinning black hole in the Cyg X-I system. Key words. accretion, accretion disks - black hole physics - X-rays:binaries
Document ID
20110015340
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Nowak, M. A.
(Massachusetts Inst. of Tech. Cambridge, MA, United States)
Wilms, J.
(Erlangen-Nuernberg Univ. Bamberg, Germany)
Hanke, M.
(Erlangen-Nuernberg Univ. Bamberg, Germany)
Pottschmidt, K.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Markoff, S.
(Amsterdam Univ. Netherlands)
Date Acquired
August 25, 2013
Publication Date
January 1, 2011
Publication Information
Publication: Memorie della Societa Astronomica Italiana
Volume: 1
Subject Category
Astrophysics
Report/Patent Number
GSFC.JA.4889.2011
Funding Number(s)
CONTRACT_GRANT: NNX07AF71G
CONTRACT_GRANT: NNX08AZ66G
CONTRACT_GRANT: NNX08AE23G
CONTRACT_GRANT: GO8-9036X
CONTRACT_GRANT: NNG06EO90A
CONTRACT_GRANT: GO1-12065X
Distribution Limits
Public
Copyright
Other

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