TITLE: GCN CIRCULAR NUMBER: 16755 SUBJECT: Konus-Wind observation of GRB 140825A DATE: 14/08/29 17:23:14 GMT FROM: Anastasia Tsvetkova at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: The long-duration, intense GRB 140825A (IPN triangulation: Hurley et al., GCN 16752) triggered Konus-Wind at T0=24925.66 s UT (06:55:25.660). The burst light curve shows several peaks with a total duration of ~14 s. The emission is seen up to ~10 MeV. As observed by Konus-Wind, the burst had a fluence of 3.7(-0.2,+0.2)x10^-5 erg/cm2, and a 64-ms peak energy flux, measured from T0+1.984 s, of 1.4(-0.2,+0.2)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum of the burst (measured from T0 to T0+10.752 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.94(-0.07,+0.08), the high-energy photon index beta = -3.42(-1.36,+0.40), the peak energy Ep = 142(-7,+7) keV, chi2 = 86/84 dof. The spectrum near the peak count rate (measured from T0+2.048 to T0+2.560 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.44(-0.15,+0.21), the high-energy photon index beta = -3.42(-1.61,+0.59), the peak energy Ep = 208(-23,+18) keV, chi2 = 41/44 dof. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB140825_T24925/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.