The Astrophysical Journal · 1994 · 25 citations · 0 references
Natural SciencesAstronomyPhysicsAstrophysicsObservational AstronomyX-ray AstronomyExtragalactic Gamma-ray AstronomyExtragalactic X-ray SourcesGamma-ray BurstsGamma-ray SourcesHigh-energy Astrophysical SourcesEmission Spectral AnalysisGamma-ray Burst ObservationsHigh-energy Gamma-ray AstronomyTransient Source DetectionTransient X-ray SourcesX-ray Spectra
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.