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1991 October 12 (C9.2)
A GOES C9.2 solar flare occurred on 1991 October 12 at an H-alpha location of S27E31 (heliographic coordinates). The soft X-ray flux began at 04:56 (17760 s), peaked at 05:07 (18420 s) and ended at 05:12 (18720 s) UT (GOES Geophysical Data Web Site). OSSE received a BATSE transient trigger at 18323 s and the four OSSE detectors slewed to the scan-angle position of the Sun. Two of the four detectors then initiated +/- 4.5 degree on-source-off-source viewing strategies while the other two detectors remained pointed at the Sun.
Significant emmission of up to about 600 keV was observed during a ~30 s time interval (18368-18398 s). Count rate time profiles in various energy windows at a temporal resolution of ~8 s are shown in Figure 1. A representative count spectrum is shown in Figure 2. A single power law with an index of about -3.0 was used to fit the data. The total fluence above 50 keV was 34.1 +/- 1.0 photons cm-2.
 Figure 1 |
 Figure 2 |