The Gamma-ray Spectral Variability of Cygnus X-1

Details The Gamma-ray Spectral Variability of Cygnus X-1 The Gamma-ray Spectral Variability of Cygnus X-1

Dec 1992

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992aas...181.2002m&link_type=abstract

American Astronomical Society, 181st AAS Meeting, #20.02; Bulletin of the American Astronomical Society, Vol. 24, p.1153

Astronomy and Astrophysics

Astronomy

Scientific paper

The long-term transitions of the black hole candidate Cygnus X-1 (between the states gamma_1 , gamma_2 , and gamma_3 ) include the occasional appearance of a strong ~ MeV bump (gamma_1 ), whose strength appears to be anti-correlated with the continuum flux (alt 400 keV) due to the Compton upscattering of cold disk photons by the inner, hot corona. We develop a self-consistent disk picture that accounts naturally for these transitions and their corresponding spectral variations. We argue that the bump is due to the self-Comptonization of bremsstrahlung photons emitted predominantly near the plane of the corona itself. Our results suggest that a decrease by a factor of ~ 2 in the viscosity parameter alpha is responsible for quenching this bump and driving the system to the gamma_2 state, whereas a transition from gamma_2 to gamma_3 appears to be induced by an increase of about 25% in the accretion rate dot M. In view of the fact that most of the transitions observed in this source seem to be of the gamma_2 -gamma_3 variety, we conclude that much of the long term gamma-ray spectral variability in Cygnus X-1 is due to these small fluctuations in dot M. The unusual appearance of the gamma_1 state apparently reflects a change in the dissipative processes within the disk.

Affiliated with

Also associated with

No associations

Rating

The Gamma-ray Spectral Variability of Cygnus X-1 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The Gamma-ray Spectral Variability of Cygnus X-1, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Gamma-ray Spectral Variability of Cygnus X-1 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1110339