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1991 November 11 (C5.9)

A GOES C5.9 solar flare occurred on 1991 November 11 at an H-alpha location of S14E36 (heliographic coordinates). The soft X-ray flux began at 16:34 (59640 s), peaked at 16:40 (60000 s) and ended at 16:44 (60240 s) UT (GOES Geophysical Data Web Site). OSSE received a BATSE transient trigger at 59850 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. Because of the extreme DSA-angle of the Sun, however, the views of the top two detectors were obstructed and significant data were recorded by only the bottom two detectors.

Significant emission of up to about 300 keV was observed during a ~275 s time interval (59855-60130). 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 -3.6 was used to fit the data. The total fluence above 50 keV was 199.5 +/- 6.4 photons cm-2.

Figure 1

Figure 2

Last revised: 27 Jul 1999