TITLE: GCN CIRCULAR NUMBER: 15095 SUBJECT: Konus-Wind observation of GRB 130812B DATE: 13/08/13 16:53:48 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline, on behalf of the Konus-Wind team, report: The long-duration ûùàå-ûçóñåêãü GRB 130812B (IPN triangulation: Hurley at al., GCN 15094) triggered Konus-Wind at T0=39316.109 s UT (10:55:16.109). The light curve shows multiple pulses from ~T0-0.5 s to ~T0+16s followed by a weak decaying emission during the next ~15 s. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB130812_T39316/ As observed by Konus-Wind, the burst had a fluence of (1.52 ± 0.03)x10-5 erg/cm2, and a 64-ms peak flux, measured from T0+4.032s, of (3.5 ± 0.3)x10-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum (measured from T0 to T0+33.024 s) is best fit in the 20 keV - 15 MeV range by the cutoff power law with the following model parameters: the photon index alpha = -1.33 ± 0.07, the peak energy Ep = 78 ± 3 keV, chi2 = 90/98 dof. The time-averaged spectrum of the bright phase of the burst (measured from T0 to T0+16.640 s) is best fit in the 20 keV - 15 MeV range by the cutoff power law with the following model parameters: the photon index alpha = -1.04 ± 0.07, the peak energy Ep = 90 ± 2 keV, chi2 = 75/97 dof. All the quoted results are preliminary.