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1999 August 02 (C6.9)
A GOES C6.9 solar flare occurred on 1999 August 02 at an H-alpha location of S30W29 (heliographic coordinates). The soft X-ray flux began at 14:43 (52980 s), peaked at 14:50 (53400 s), and ended at 14:54 (53640 s) UT (GOES Geophysical Data Web Site). OSSE received a BATSE solar-flare trigger at 53158 s. All OSSE detectors were already aimed at the sun. Two detectors remained in the same position throughout the entire flare while the other two detectors performed a standard on-source-off-source viewing strategy.
Significant gamma-ray emission to ~200 keV was observed lasting until about 53150 s UT with one peak of emission at ~53190 s. Count rate time profiles in various energy windows at a temporal resolution of ~8 s are shown in Figure 1. Figure 2 shows a representative count spectrum obtained from one Sun-pointed detector integrated over the time period 53155-53237 s UT (82 seconds). The electron bremsstrahlung component was well-fit with a simple power law having a spectral index of ~5.00. There was no evidence for nuclear lines.
 Figure 1 |
 Figure 2 |