TITLE: GCN CIRCULAR NUMBER: 12433 SUBJECT: Konus-Wind observation of GRB 111008A DATE: 11/10/09 14:58:01 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 long GRB 111008A (Swift-BAT trigger #505054: Saxton et al., GCN 12433; Baumgartner et al., GCN 12434) triggered Konus-Wind at T0=79981.676s UT (22:13:01.676) The burst light curve shows an initial pulse which peaked at T0+0.256s and a softer weaker pulse at ~T0+30s. A total burst duration is ~40 s. The emission is seen up to ~2 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB111008_T79981/ As observed by Konus-Wind the burst had a fluence of (9.0 ± 0.9)x10-6 erg/cm2, and a 256-ms peak flux, measured from T0+0.256 s, of (1.4 ± 0.3)x10-6 erg/cm2/s (both in the 20 keV - 2 MeV energy range). The time-integrated spectrum of the burst (measured from T0 to T0+41.216 s) is best fitted in the 20 keV - 2 MeV range by a simple power-law model with index (2.02 ± 0.09), chi2 = 54.3/59 dof. The spectrum of the initial pulse (measured from T0 to T0+8.448 s) is best fitted in the 20 keV - 2 MeV range by a power law with exponential cutoff model, for which alpha = -1.36 (-0.21, +0.24), and Ep = 149(-28, +52) keV, chi2 = 38.4/58 dof. Assuming the redshift z=5.0 (Levan et al., GCN 12429; Wiersema et al., GCN 12431) and a standard cosmology model with H_0 = 71 km/s/Mpc, Omega_M = 0.27, Omega_Lambda = 0.73, the isotropic energy release E_iso is (4.1 ± 0.4)x10^53 erg, the isotropic peak luminosity L_iso_max is (3.8 ± 0.7)x10^53 erg/s, and Ep_rest is 894(-168,+312) keV (the initial pulse spectrum). All the quoted results are preliminary. All the quoted errors are at the 90% confidence level.