TITLE: GCN CIRCULAR NUMBER: 15530 SUBJECT: Konus-Wind observation of GRB 131127B DATE: 13/11/28 13:06:06 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 bright, long-duration GRB 131127B (Fermi GBM detection: von Kienlin, GCN 15528; IPN triangulation: Golenetskii at al., GCN 15529) triggered Konus-Wind at T0=51139.678 s UT (14:12:19.678). The burst light curve shows multiple overlapped pulses from ~T0-0.5 s to ~T0+20 s. The emission is seen up to ~12 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB131127_T51139/ As observed by Konus-Wind, the burst had a fluence of (4.1 ± 0.3)x10-5 erg/cm2, and a 64-ms peak flux, measured from T0+4.160 s, of (1.15 ± 0.08)x10-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum (measured from T0 to T0+21.760 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -1.20 ± 0.11, the high energy photon index beta = -2.51 ± 0.19, the peak energy Ep = 165 ± 17 keV, chi2 = 140/97 dof. The spectrum near the maximum count rate (measured from T0 to T0+5.376 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.92 ± 0.14, the high energy photon index beta = -2.43 ± 0.19, the peak energy Ep = 218 ± 27 keV, chi2 = 128/97 dof. All the quoted values are preliminary.