{
  "bibcode": "1999GCN...317....1A",
  "body": "L. Amati, F. Frontera (ITESRE/CNR, Bologna), E. Costa, M. Feroci \n(IAS/CNR, Rome), on behalf of the BeppoSAX/GRBM team, report:\n\nGRB990510 was detected by the BeppoSAX Gamma Ray Burst Monitor (see\nalso IAUC #7160) as a bright, complex gamma-ray burst composed by two well\nseparated and multi-peaked pulses with a total duration of about 75 s. The\nGRB fluence in the 40-700 keV energy range is (1.9 +/- 0.2) x 10E-5 erg\ncmE-2, while its peak flux (integrated on 1 s, same energy band) is (2.4\n+/- 0.2) x 10E-6 erg cmE-2 sE-1.  For comparison, the peak flux in the\n2-28 keV range as measured by the BeppoSAX/WFC N. 2 (IAUC #7160) is \n1.4 x 10E-7 erg cmE-2 sE-1. The fluence of the event is the highest,\namong the BeppoSAX localized events, after GRB990123, GRB980329, and\nGRB970111. The burst shows typical hard-to soft spectral evolution with an\naverage power law photon index of  1.8 +/- 0.1 in the 70-650 keV energy\nband.\n\nThis message is citeable.",
  "circularId": 317,
  "createdOn": 926451350000,
  "email": "filippo@tesre.bo.cnr.it",
  "subject": "GRB 990510: BeppoSAX/GRBM observations",
  "submitter": "Filippo Frontera at ITESRE CNR  <filippo@tesre.bo.cnr.it>",
  "eventId": "GRB 990510"
}