TITLE: GCN GRB OBSERVATION REPORT NUMBER: 442 SUBJECT: GRB 991105: BATSE Observations DATE: 99/11/08 23:18:20 GMT FROM: R. Marc Kippen at BATSE/UAH/MSFC R. M. Kippen, S. Phengshamnan & T. Giblin (University of Alabama in Huntsville) report on behalf of the BATSE GRB team: GRB 991105 was detected by BATSE on 1999 November 5.694963 UT as trigger number 7841. The event consisted of a complex series of pulses with two major episodes and significant spectral evolution. The T50 and T90 durations are 12.35 (-/+ 1.90) s and 48.64 (-/+ 1.36) s, respectively. The burst's peak flux (50-300 keV; integrated over 1.024 s) and fluence (>20 keV) are 1.98 (-/+ 0.06) photons cmE-2 sE-1 and 4.01 (-/+ 0.79) x 10E-6 erg cmE-2, respectively---ranking it in the top 20% (38%) 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 = 0.83 (-/+ 0.01), which is average for bursts of this duration. The BATSE burst location is consistent with those measured by BeppoSAX (GCN 430) and the IPN (SAX/NEAR; GCN 411). The lightcurve for this event will be available shortly at: http://gammaray/batse/grb/lightcurve/