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GCN Circular 1045

Possible precursor to the SGR1900+14 giant burst
2001-04-20T19:48:21Z (23 years ago)
Kevin Hurley at UCBerkeley/SSL <>
K. Hurley, on behalf of the Ulysses GRB team, and E. Montanari, C. Guidorzi,
F. Frontera, and M. Feroci, on behalf of the BeppoSAX GRBM team, report:

We have identified a likely precursor to the giant flare from
SGR1900+14 (GCN 1041, 1043) in the Ulysses data.  This event
occurred on April 17, 2001, ~42184 s at Ulysses, and if it was
indeed from SGR1900+14, its Earth-crossing time would have
been ~42332 s.  This burst was ~50 s long, and its time history
resembles that of the April 18 event, although it is considerably
less intense.  Its 25-100 keV fluence was ~2.3x10^-5 erg/cm^2,
and its peak flux over 0.5 s was ~1.5x10^-6 erg/cm^2 s.  Due to
a high solar proton background, these numbers are subject to more
than the usual uncertainties.  As SGR1900+14 was Earth-blocked
at BeppoSAX, it did not observe this event, and there is no
localization data available.

The time history has been posted at
Also, we note that the time history of the April 18 event, posted
at, was incorrectly labelled "Counts/
0.5 s".  The label should have read "Counts/Second".  A corrected
plot has been posted.

Searches are underway through the Ulysses data for more possible
events from this source.
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