TITLE: GCN CIRCULAR NUMBER: 8926 SUBJECT: Konus-Wind observation of bright short GRB 090227B DATE: 09/03/03 16:01:32 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 bright short hard GRB 090227B (Fermi/GBM trigger 257452263 / 090227772: Guiriec, GCN 8921) localized by IPN (Golenetskii et al., GCN 8925) triggered Konus-Wind at T0=66659.079 s UT (18:30:59.079). As observed by Konus-Wind the burst had a fluence of (2.75 +/- 0.27)x10^-5 erg/cm2, and a 16-ms peak flux measured from T0+0.008 s of 3.98(-0.58, +0.59)x10^-4 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum of the burst (from T0 to T0+0.192 s) is well fitted (in the 20 keV - 10 MeV range) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.43(-0.09, +0.10), and Ep = 2253(-262, +292) keV (chi2 = 29.4/47 dof). Fitting by GRB (Band) model yields: the low-energy photon index alpha = -0.41(-0.10, +0.12), the high energy photon index beta < -2.5, the peak energy Ep = 2134(-326, +332) keV (chi2 = 28.1/46 dof). The emission is clearly seen up to 10 MeV. All the quoted errors are at the 90% confidence level.