TITLE: GCN CIRCULAR NUMBER: 10948 SUBJECT: Konus-Wind observation of GRB 100707A DATE: 10/07/09 10:09:17 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 very bright long GRB 100707A (Fermi/GBM trigger 300156400: Wilson-Hodge and Foley, GCN 10944; localized by IPN: Hurley et al., GCN 10947) triggered Konus-Wind at T0=2798.855s UT (00:46:38.855) The burst light curve consists of a single FRED pulse with a duration of ~100 s. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB100707_T02798/ The periodic dips seen in the 64-ms lc are caused by the occultation of the Konus detector by other instrument on board the rotating Wind s/c. As observed by Konus-Wind the burst had a fluence of 8.8(+/-0.6)x10-5 erg/cm2, and a 64-ms peak flux measured from T0+1.344s of 2.4(+/- 0.2)x10-5 erg/cm2/s (both in the 20 keV - 2 MeV energy range). The time-integrated spectrum of the burst (from T0 to T0+102.144 s) is best fit in the 20 keV - 2 MeV range by the GRB (Band) model, for which: the low-energy photon index alpha = -0.95 (+/-0.15), the high energy photon index beta = -2.2 (-0.3, +0.2), the peak energy Ep = 264(-40, +49)keV (chi2 = 43.5/57 dof). The spectrum at the maximum count rate (measured from T0+1.280 to T0+1.792 s) is best fit in the 20 keV - 2 MeV range by the GRB (Band) model, for which: the low-energy photon index alpha = +0.3 (-0.3, +0.5), the high energy photon index beta = -2.4 (-0.5, +0.3), the peak energy Ep = 383(-82, +80)keV (chi2 = 53.2/57 dof). All the quoted results are preliminary. All the quoted errors are at the 90% confidence level.