TITLE: GCN CIRCULAR NUMBER: 15639 SUBJECT: Konus-Wind observation of GRB 131229A DATE: 13/12/31 14:32:55 GMT FROM: Dmitry Svinkin at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 131229A (Swift-BAT trigger 582374: Page et al., GCN 15627) triggered Konus-Wind at T0=23970.560 s UT (06:39:30.560). The burst light curve shows a multi-peaked structure with a total duration of ~17 s. The emission is seen up to ~1.5 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB131229_T23970/ As observed by Konus-Wind, the burst had a fluence of 2.45(-0.17,+0.18)x10-5 erg/cm2, and a 64-ms peak flux, measured from T0+10.976 s, of 1.07(-0.15,+0.15)x10-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum (measured from T0 to T0+13.056 s) is best fit in the 20 keV - 1.5 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep), alpha = -0.65(-0.10,+0.11), and Ep = 352(-28,+34) keV (chi2 = 51.9/60 dof). The spectrum near the maximum count rate (measured from T0+8.448 to T0+13.056 s) is best fit in the 20 keV - 1.5 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep), alpha = -0.43(-0.10,+0.11), and Ep = 366(-24,+28) keV (chi2 = 58.6/60 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.