Статья

<i>NuSTAR</i>AND<i>SUZAKU</i>OBSERVATIONS OF THE HARD STATE IN CYGNUS X-1: LOCATING THE INNER ACCRETION DISK

M. L. ParkerInstitute of Astronomy, Madingley Road, Cambridge, CB3 0HA, UKJohn A. TomsickSpace Sciences Laboratory, University of California, Berkeley, 7 Gauss Way, Berkeley, CA 94720-7450, USAJ. M. MïllerDepartment of Astronomy, University of Michigan, 1085 South University Avenue, West Hall 311, Ann Arbor, MI 48109-1042, USAK. YamaokaSolar-Terrestrial Environment Laboratory, Department of Particles and Astronomy, Nagoya University, Furocho, Chikusa-ku, Nagoya, Aichi 464-8601, JapanA. LohfinkInstitute of Astronomy, Madingley Road, Cambridge, CB3 0HA, UKMichael A. NowakMassachusetts Institute of Technology, Kavli Institute for Astrophysics, Cambridge, MA 02139, USAA. C. FabianInstitute of Astronomy, Madingley Road, Cambridge, CB3 0HA, UKWilliam AlstonInstitute of Astronomy, Madingley Road, Cambridge, CB3 0HA, UKSteven E. BoggsSpace Sciences Laboratory, University of California, Berkeley, 7 Gauss Way, Berkeley, CA 94720-7450, USAFinn E. ChristensenDanish Technical University, DK-2800 Lyngby, DenmarkWilliam W. CraigLawrence Livermore National Laboratory, Livermore, CA 94550, USAFelix FürstCalifornia Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USAP. GandhiSchool of Physics & Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ, UKBrian W. GrefenstetteCalifornia Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USAV. GrinbergMassachusetts Institute of Technology, Kavli Institute for Astrophysics, Cambridge, MA 02139, USACharles J. HaileyColumbia University, New York, NY 10027, USAFiona A. HarrisonCalifornia Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USAErin KaraInstitute of Astronomy, Madingley Road, Cambridge, CB3 0HA, UKA. L. KingDepartment of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, CA 94305, USADaniel SternJet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USAD. J. WaltonCalifornia Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USAJ. WilmsDr Karl Remeis-Observatory and Erlangen Centre for Astroparticle Physics, Sternwartstrasse 7, D-96049 Bamberg, GermanyW. W. ZhangNASA Goddard Space Flight Center, Greenbelt, MD 20771, USA

2015en

ABI

Аннотация

We present simultaneous Nuclear Spectroscopic Telescope Array (NuSTAR ) and Suzakuobservations of the X-ray binary Cygnus X-1 in the hard state. This is the first time this state has been observed in Cyg X-1 with NuSTAR, which enables us to study the reflection and broadband spectra in unprecedented detail. We confirm that the iron line cannot be fit with a combination of narrow lines and absorption features, instead requiringa relativistically blurred profile in combination with a narrow line and absorption from the companion wind. We use the reflection models of Garca et al. to simultaneously measure the black hole spin, disk inner radius, and coronal height in a self-consistent manner. Detailed fits to the iron line profile indicate a high level of relativistic blurring, indicative of reflection from the inner accretion disk. We find a high spin, a small inner disk radius, and a low source heightand rule out truncation to greater than three gravitational radii at the 3 confidence level. In addition, we find that the line profile has not changed greatly in the switch from soft to hard states, and that the differences are consistent with changes in the underlying reflection spectrum rather than the relativistic blurring. We find that the blurring parameters are consistent when fitting either just the iron line or the entire broadband spectrum, which is well modeled with a Comptonized continuum plus reflection model.

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Идентификаторы

DOI: 10.1088/0004-637x/808/1/9

Цитирования и источники

Цитирований: 3Использованных источников: 0

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