Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 317

GRB 990510: BeppoSAX/GRBM observations
1999-05-11T19:35:50Z (25 years ago)
Filippo Frontera at ITESRE CNR <>
L. Amati, F. Frontera (ITESRE/CNR, Bologna), E. Costa, M. Feroci 
(IAS/CNR, Rome), on behalf of the BeppoSAX/GRBM team, report:

GRB990510 was detected by the BeppoSAX Gamma Ray Burst Monitor (see
also IAUC #7160) as a bright, complex gamma-ray burst composed by two well
separated and multi-peaked pulses with a total duration of about 75 s. The
GRB fluence in the 40-700 keV energy range is (1.9 +/- 0.2) x 10E-5 erg
cmE-2, while its peak flux (integrated on 1 s, same energy band) is (2.4
+/- 0.2) x 10E-6 erg cmE-2 sE-1.  For comparison, the peak flux in the
2-28 keV range as measured by the BeppoSAX/WFC N. 2 (IAUC #7160) is 
1.4 x 10E-7 erg cmE-2 sE-1. The fluence of the event is the highest,
among the BeppoSAX localized events, after GRB990123, GRB980329, and
GRB970111. The burst shows typical hard-to soft spectral evolution with an
average power law photon index of  1.8 +/- 0.1 in the 70-650 keV energy

This message is citeable.
Looking for U.S. government information and services? Visit