Journal article ยท Preprint article
The Reflection Component from Cygnus X-1 in the Soft State Measured by NuSTAR and Suzaku
Massachusetts Institute of Technology1
National Institute for Astrophysics2
NASA Goddard Space Flight Center3
College of the Holy Cross4
NASA Jet Propulsion Laboratory5
Erlangen Centre for Astroparticle Physics6
University of Michigan, Ann Arbor7
University of Cambridge8
California Institute of Technology9
CNRS10
University of California at Berkeley11
National Space Institute, Technical University of Denmark12
Astrophysics, National Space Institute, Technical University of Denmark13
Columbia University14
...and 4 moreThe black hole binary Cygnus X-1 was observed in late-2012 with the Nuclear Spectroscopic Telescope Array (NuSTAR) and Suzaku, providing spectral coverage over the ~1-300 keV range. The source was in the soft state with a multi-temperature blackbody, power-law, and reflection components along with absorption from highly ionized material in the system.
The high throughput of NuSTAR allows for a very high quality measurement of the complex iron line region as well as the rest of the reflection component. The iron line is clearly broadened and is well-described by a relativistic blurring model, providing an opportunity to constrain the black hole spin.
Although the spin constraint depends somewhat on which continuum model is used, we obtain a*>0.83 for all models that provide a good description of the spectrum. However, none of our spectral fits give a disk inclination that is consistent with the most recently reported binary values for Cyg X-1. This may indicate that there is a >13 degree misalignment between the orbital plane and the inner accretion disk (i.e., a warped accretion disk) or that there is missing physics in the spectral models.
Language: | English |
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Publisher: | American Astronomical Society |
Year: | 2014 |
Pages: | 78 |
ISSN: | 15384357 and 0004637x |
Types: | Journal article and Preprint article |
DOI: | 10.1088/0004-637X/780/1/78 |
ORCIDs: | Christensen, Finn Erland |