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GCN Circular 224

GRB 990123: BATSE Observations
1999-01-25T22:18:55Z (25 years ago)
R. Marc Kippen at BATSE/UAH/MSFC <>
R. M. Kippen (University of Alabama in Huntsville) reports on behalf
of the BATSE GRB team:

GRB 990123 was detected by BATSE on 1998 January 23.407594 as trigger
number 7343.  The event was strong and consisted of a multi-peaked
temporal structure lasting >100 s, with significant spectral
evolution.  The T50 and T90 durations are 29.82 (-/+ 0.10) s and 63.30
(-/+ 0.26) s, respectively.  The burst's peak flux (50-300 keV;
integrated over 1.024 s) and fluence (>20 keV) are 16.42 (-/+ 0.12)
photons cmE-2 sE-1 and 5.09 (-/+ 0.02) x 10E-4 erg cmE-2,
respectively---ranking it in the top 2% (0.3%) of the BATSE burst flux
(fluence) distribution.  The average spectral hardness of the burst,
as estimated by the ratio of 100-300 keV counts to those in the 50-100
keV range, is H32 = 1.51 (-/+ 0.004), which is average among BATSE
bursts.  The BATSE burst location is consistent with those measured by
BeppoSAX (GCN 199,202,203) and with the proposed optical/radio
transient counterpart (GCN 201; 204-221).  A location sky-map and
lightcurve for this event (and other notable bursts) are available at
the BATSE Rapid Burst Response world-wide-web site:

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