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Hard x-ray emission (20-320 keV) from the black hole candidate GX339-4 was studied using the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory (CGRO). The source was monitored on a daily basis during 120-day hard state outbursts in 1991 and 1992 using Earth occultation measurements of its energy spectrum and power density spectra of time-binned data (frequency range 0.005-0.5 Hz). We find considerable spectral evolution during the outbursts similar to other black hole candidates and at least two days where quasi-periodic oscillations are present in the power spectrum at 0.027 Hz (37 s). We examine the long-term behavior of the photon spectra of GX339-4 and integrated power spectra for possible correlations.
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