TITLE: GCN CIRCULAR NUMBER: 12270 SUBJECT: Konus-Wind observation of GRB 110808A DATE: 11/08/11 10:30:42 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 extremely hard GRB 110808A (localized by IPN: Hurley et al., GCN 12269) triggered Konus-Wind at T0=56695.237s UT (15:44:55.237) The burst light curve shows a single bright hard pulse, with a duration of ~0.5 s and much weaker tail of the emission which is detectable till T0+8 s. The emission is seen up to 13 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB110808_T56695/ As observed by Konus-Wind the burst had a fluence of (1.6 ± 0.2)x10-5 erg/cm2, and a 16-ms peak flux, measured from T0+0.112 s, of (1.1 ± 0.2)x10-4 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 fitted in the 20 keV - 10 MeV range by a power law with exponential cutoff model, for which alpha = -1.13 (-0.08, +0.08), and Ep = 2960(-796, +1217) keV, chi2 = 53.2/45 dof. Fitting this spectrum by the GRB (Band) function yields the following model parameters: the low-energy photon index alpha = -1.13 (-0.08, +0.07), the high energy photon index beta = -2.5 (<-1.9), the peak energy Ep = 2630(-744, +836) keV, chi2 = 54.3/44 dof. The spectrum at the maximum count rate (measured from T0+0.064 to T0+0.128 s) is best fitted in the 20 keV - 10 MeV range by a power law with exponential cutoff model, for which alpha = -1.07 (-0.11, +0.12), and Ep = 4238(-1530, +3270) keV, chi2 = 12.5/16 dof. All the quoted results are preliminary. All the quoted errors are at the 90% confidence level.