NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
RXTE Observation of Cygnus X-1 Spectral AnalysisWe present the results of the analysis of the broad-band spectrum of Cygnus X-1 from 3.0 to 200 keV, using data from a 10 ksec observation by the Rossi X-ray Timing Explorer. Although the spectrum can be well described phenomenologically by an exponentially cut-off power law (photon index Gamma = 1.45+0.01 -0.02 , e-folding energy e(sub f) = 162+9 -8 keV, plus a deviation from a power law that formally can be modeled as a thermal blackbody, with temperature kT(sub BB) = 1.2 +0.0 -0.1 keV), the inclusion of a reflection component does not improve the fit. As a physical description of this system, we apply the accretion disc corona (ADC) models. A slab-geometry ADC model is unable to describe the data. However, a spherical corona, with a total optical depth tau- = 1.6 + or - 0.1 and an average temperature kTc = 87 + or - 5 keV, surrounded by an exterior cold disc, does provide a good description of the data (X red (exp 2) = 1.55). These models deviate from the data bv up to 7% in the 5-10 keV range. However, considering how successfully the spherical corona reproduces the 10-200 keV data, such "photon-starved" coronal geometries seem very promising for explaining the accretion processes of Cygnus X-1.
Document ID
19990027827
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Dove, J. B.
(Wyoming Univ. Laramie, WY United States)
Wilms, Joern
(Tuebingen Univ. Germany)
Nowak, M. A.
(Colorado Univ. Boulder, CO United States)
Vaughan, B. A.
(California Inst. of Tech. Pasadena, CA United States)
Begelman, M. C.
(Colorado Univ. Boulder, CO United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1998
Publication Information
Publication: Nuclear Physics B: Proceedings Supplements
Publisher: Elsevier Science B.V.
Volume: 69/1
ISSN: 0920-5632
Subject Category
Astronomy
Funding Number(s)
CONTRACT_GRANT: NAG5-3225
CONTRACT_GRANT: DARA-50-OR-92054
CONTRACT_GRANT: NAG5-3310
CONTRACT_GRANT: NSF AST-95-29175
CONTRACT_GRANT: NAG5-2026
CONTRACT_GRANT: NSF AST-91-20599
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available