  The flux and spectrum of the black hole candidate GX339-4 has been monitored
by the Burst and Transient Source Experiment (BATSE) on the Compton Gamma-ray
Observatory (CGRO) since the observatory became operational in May 1991.
Between the summer of 1991 and the fall of 1996, eight outbursts from GX339-4
were observed. The history of these outbursts is one of declining fluence or
total energy release, as well as a shortening of the time between outbursts. A
rough linear correlation exists between the fluence emitted during an outburst
and the time elapsed between the end of the previous outburst and the beginning
of the current one. The peak flux is also roughly linearly correlated with
outburst fluence. The lightcurves of the earlier, more intense, outbursts
(except for the second one) can be modeled by a fast exponential (time constant
~ 10 days) followed by a slower exponential (~ 100 days) on the rise and a fast
exponential decay (~ 5 days) on the fall. The later, weaker, outbursts are
modeled with a single rising time constant (~ 20 days) and a longer decay on
the fall (~ 50 days). An exponential model gives a marginally better fit than a
power law to the rise/decay profiles. GX339-4 is a unique source in having more
frequent outbursts than other low mass x-ray binary black hole candidates.
These observations can be used to constrain models of the behavior of the
accretion disk surrounding the compact object.
