TITLE: GCN CIRCULAR NUMBER: 12532 SUBJECT: Konus-Wind observation of GRB 111103B DATE: 11/11/05 13:12:31 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report: The long GRB 111103B (Swift-BAT trigger #505054: Grupe et al., GCN 12519; Barthelmy et al., GCN 12524) triggered Konus-Wind at T0=39541.020s UT (10:59:01.020) The light curve shows a ~15 s long pulse followed by a weaker activity continuing till ~(T0+40)s. The second group of peaks observed by Swift/BAT after T0+100 is poorly determined in the Konus-Wind light curves against the background of a rising M2.5 Solar flare. The emission in the initial peak complex is seen up to ~4 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB111103_T39541/ As observed by Konus-Wind the burst had a fluence of (2.0 +/-0.3)x10-5 erg/cm2, and a 256-ms peak flux, measured from T0+5.120 s, of (2.7 +/-0.4)x10-6 erg/cm2/s (both in the 20 keV - 5 MeV energy range). The time-integrated spectrum of the burst (measured from T0 to T0+41.216 s) is best fitted in the 20 keV - 5 MeV range by a power law with exponential cutoff model, for which alpha = -0.97 (-0.18, +0.19), and Ep = 372(-69, +109) keV, chi2 = 77.2/77 dof. Fitting this spectrum by the GRB (Band) function yields the same alpha and Ep with a high energy photon index beta < -2.2 (chi2 = 77.1/76 dof). The spectrum at the maximum count rate (measured from T0 to T0+6.144 s) is best fitted in the 20 keV - 5 MeV range by a power law with exponential cutoff model, for which alpha = -0.97 (-0.12, +0.14), and Ep = 393(-55, +76) keV, chi2 = 70.2/77 dof. All the observed properties are typical for a moderately intense long gamma-ray burst and don't argue for a Galactic transient hypothesis. All the quoted results are preliminary. All the quoted errors are at the 90% confidence level.