TITLE: GCN CIRCULAR NUMBER: 13621 SUBJECT: Konus-Wind observation of GRB 120811B DATE: 12/08/11 13:28:20 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 short-duration hard GRB 120811B (IPN localization: Golenetskii at al., GCN 13620) triggered Konus-Wind at T0=01231.575s UT (00:20:31.575) The light curve shows a double pulse, a total duration of the burst is ~0.33 s. The emission is seen up to ~6 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB120811_T01231/ As observed by Konus-Wind the burst had a fluence of 4.6(-0.9,+1.0)x10-6 erg/cm2, and a 16-ms peak flux, measured from T0, of 2.8(-0.6,+0.7)x10-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The spectrum of the burst (measured from T0 to T0+0.256 s) is best fit in the 20 keV - 7 MeV range by a power law with exponential cutoff model, for which alpha = -0.14 (-0.28, +0.35), and Ep = 1130(-230, +310) keV, chi2 = 13.6/24 dof. All the quoted results are preliminary. All the quoted errors are at the 90% confidence level.