Observation of GX 339-4 hard state outbursts in 1991 and 1992

Authors :: W. S. Paciesas
Robert B. Wilson
C. A. Wilson
Martin N. Brock
B. A. Harmon
Geoffrey N. Pendleton
B. C. Rubin
Gerald J. Fishman
M. H. Finger
Michael S. Briggs
C. A. Meegan
Source :: The Astrophysical Journal. 425:L17
Publication Year :: 1994
Publisher :: American Astronomical Society, 1994.
Abstract: Two hard state (X-ray low state) outbursts in the GX 339-4 system in 1991 June-October and 1992 September-1993 January were detected and monitored by the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory (CGRO). The outbursts were remarkably similar in both temporal and spectral aspects. The spectrum in the 20-300 keV band evolves from a hard, Comptonized shape to a steeper (alpha approximately equals -3) power law during each outburst.