TITLE: GCN CIRCULAR NUMBER: 15551 SUBJECT: Konus-Wind observation of GRB 131126A DATE: 13/11/29 17:01:35 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, bright GRB 131126A (IPN Triangulation: Golenetskii et al., GCN 15550) triggered Konus-Wind at T0=14048.270 s UT (03:54:08.270). The burst light curve shows a pulse with a duration of ~140 ms. The emission is seen up to ~6 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB131126_T14048/ As observed by Konus-Wind, the burst had a fluence of (2.1 ± 0.2)x10-6 erg/cm2, and a 16-ms peak flux, measured from T0+0.016, of (2.4 ± 0.2)x10-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum (measured from T0 to T0+0.128 s) is best fit, in the 20 keV - 15 MeV range, by a cutoff power law with the following model parameters: the photon index alpha = -0.43 ± 0.14 and the peak energy Ep = 633 ± 85 keV, chi2 = 46.2/65 d.o.f. The spectrum near the maximum count rate (measured from T0 to T0+0.064 s) is best fit, in the 20 keV - 15 MeV range, by a cutoff power law with the following model parameters: the photon index alpha = -0.20 ± 0.20 and the peak energy Ep = 680 ± 100 keV, chi2 = 40.6/60 d.o.f. All the quoted results are preliminary.