TITLE: GCN CIRCULAR NUMBER: 11127 SUBJECT: Konus-Wind observation of GRB 100816A DATE: 10/08/18 11:30:01 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 GRB 100816A (Swift-BAT trigger=431764; Oates et al., GCN 11102; Markwardt et al., GCN 11111) triggered Konus-Wind at T0=02273.983s UT (00:37:53.983) The burst light curve shows a single peak with a total duration of ~2.8 s. There is also a hint of a softer (<70 keV) short (~64ms) weak spike at T0 + 4.7 s. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB100816_T02273/ As observed by Konus-Wind the burst had a fluence of (3.3 +/- 0.4)x10-6 erg/cm2, and a 64-ms peak flux measured from T0 + 0.896 s of (2.3 +/- 0.4)x10-6 erg/cm2/s (both in the 20 keV - 2 MeV energy range). The time-integrated spectrum of the burst (from T0 to T0+8.448 s) is best fit in the 20 keV - 2 MeV range by a power law with exponential cutoff model, for which alpha = -1.0(-0.3, +0.4), and Ep = 148(-26, +41) keV (chi2 = 50.5/61 dof). Fit of this spectrum by the GRB (Band) model yields the same values of alpha and Ep, with beta = -4.6 (<-2.5), chi2 = 50.5/60 dof. Assuming z=0.8049 (Tanvir et al., GCN 11123; Gorosabel et al., GCN 11125) and a standard cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.27, Omega_Lambda = 0.73, the isotropic energy release E_iso = (5.8 +/- 0.7)x10^51 erg, the peak luminosity (L_iso)_max = (7.3 +/- 1.3)x10^51 erg/s. All the quoted results are preliminary. All the quoted errors are at the 90% confidence level.