Real GRB. Very strong hard to soft spectral evolution.
Notes
HETE trigger #1959 displayed a strong hard-to-soft spectral evolution
in the first 4 seconds of the burst. The large error region published
initially was due to the extreme softness of the tail of the burst,
which introduced uncertainties in the ground imaging software.
Subsequent analyses of the harder part of the burst resulted in a better
localization.