TITLE: GCN CIRCULAR NUMBER: 9994 SUBJECT: Konus-Wind observation of GRB 091003A DATE: 09/10/05 10:14:24 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report: The long bright GRB 091003A (Fermi-GBM trigger 276237347 / 091003191: Rau, GCN 9983) localized by Fermi-LAT (McEnery et al., GCN 9985) triggered Konus-Wind at T0=16543.801 s UT (04:35:43.801). The burst light curve shows a multipeaked structure with a total duration of ~23 s. As observed by Konus-Wind the burst had a fluence of 3.44(-0.19, +0.20)x10^-5 erg/cm2, and a 16-ms peak flux measured from T0+18.592 s of (1.68 +/- 0.32)x10^-5 erg/cm2/s (both in the 20 keV - 2 MeV energy range). The time-integrated spectrum of the burst (from T0 to T0+26.880 s) is well fitted (in the 20 keV - 2 MeV range) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep), with alpha = -1.04 +/- 0.06, and Ep = 381(-36, +44) keV (chi2 = 58.4/61 dof). Fitting by GRB (Band) model yields the same alpha and Ep, and only an upper limit on the high energy photon index: beta < -2.22 (chi2 = 56.2/60 dof). All the quoted errors are at the 90% confidence level. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB091003_T16543/