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1999 July 30 (C6.1)
A GOES C6.1 solar flare occurred on July 30 1999 at an H-alpha location of N24E38 (heliographic coordinates). The soft X-ray flux began at 16:04 (57840 s), peaked at 16:06 (57900 s), and ended at 16:21 (58860 s) UT (GOES Geophysical Data Web Site). OSSE received a BATSE solar-flare trigger at 57874 s. The four OSSE detectors were already aimed towards the sun. Two remained in the same position while the other two initiated standard on-source-off-source viewing strategies.
Significant gamma-ray emission to ~150 keV was observed lasting until about 57930 s UT with one peak of emission at ~57900 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 57860-57934 s UT (74 seconds). The electron bremsstrahlung component was well-fit with a simple power law having a spectral index of ~4.73. There was no evidence for nuclear lines.
 Figure 1 |
 Figure 2 |