The states of Cygnus X-1.
Abstract
HEAO 3 High Resolution Gamma-Ray Spectrometer observations of Cygnus X-1 in the 48-300 keV range, along with correlated 3-6 keV Ariel 5 data, have led to the identification of a new state for this object with low flux in both the soft and hard X-ray regions. This is followed by a slow increase in the hard X-ray flux to the normal low state of the source, characterized by a low intensity soft X-ray emission and a high intensity hard X-ray emission. The new 'superlow' state is interpreted in terms of the Compton model, where the X-ray emission arises from the scattering of low energy photons and one-billion K hot electrons. The superlow state may be seen as one extreme of a continuum of low state behavior, given that Compton cooling should begin to quench the hot electrons at higher soft X-ray fluxes, giving rise to the softer X-ray spectrum and to the anticorrelation in changes in the soft and hard X-ray fluxes.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 1983
- DOI:
- 10.1086/161534
- Bibcode:
- 1983ApJ...275..307L
- Keywords:
-
- Cygnus Constellation;
- Gamma Ray Astronomy;
- X Ray Sources;
- Compton Effect;
- Heao 3;
- X Ray Spectra;
- Astrophysics