TITLE: GCN CIRCULAR NUMBER: 15549 SUBJECT: Konus-Wind observation of GRB 131125A DATE: 13/11/29 15:52:50 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 short-duration, hard-spectrum GRB 131125A (IPN Triangulation: Golenetskii et al. GCN 15546) triggered Konus-Wind at T0=59572.927 s UT (16:32:52.927). The burst duration is ~0.5 s. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB131125_T59572/ As observed by Konus-Wind, the burst had a fluence of (1.3 ± 0.2)x10-6 erg/cm2, and a 64-ms peak flux, measured from T0-0.064, of (5.7 ± 1.2)x10-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The 3-channel time-integrated spectrum (measured from T0-0.448 to T0+0.064 s) can be modeled, in the 22 keV - 1.3 MeV range, by the cutoff power law with the following model parameters: the photon index alpha = 0.00 ± 0.13, and the peak energy Ep = 638 ± 62 keV. The 3-channel spectrum at the maximum count rate (measured from T0-0.064 s to T0) can be modeled, in the 22 keV - 1.3 MeV range, by the cutoff power law with the following model parameters: the photon index alpha = +0.2 ± 0.3, and the peak energy Ep = 665 ± 113 keV. All the quoted results are preliminary.