TITLE: GCN CIRCULAR NUMBER: 12905 SUBJECT: Konus-Wind observation of GRB 120129A DATE: 12/01/31 10:18:12 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report: The long intense GRB 120129A (localized by IPN: Golenetskii et al., GCN 12904) triggered Konus-Wind at T0=50148.403s UT (13:55:48.403). The observation is performed against very high and variable background count rate caused by solar charged particles. The burst light curve shows two bright partly overlapped pulses. A total duration of the burst is ~4 s. The emission is seen up to ~5 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB120129_T50148/ As observed by Konus-Wind the burst had a fluence of (2.7 ± 0.7)x10-5 erg/cm2, and a 16-ms peak flux, measured from T0+0.672 s, of (3.3 ± 1.0)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+3.328 s) is best fitted in the 20 keV - 5 MeV range with the GRB (Band) model, for which: the low-energy photon index alpha = -0.76 (-0.09, +0.09), the high energy photon index beta = -2.9 ( <-2.3), the peak energy Ep = 326(-38, +52) keV, chi2 = 66.5/76 dof. The spectrum at the maximum count rate (measured from T0+0.512 to T0+0.768 s) is best fitted is best fitted in the 20 keV - 5 MeV range with the GRB (Band) model, for which: the low-energy photon index alpha = -0.51 (-0.19, +0.21), the high energy photon index beta = -2.3 (-1.4, +0.3), the peak energy Ep = 317(-66, +92) keV, chi2 = 54.2/61 dof. All the quoted results are preliminary. All the quoted errors are at the 90% confidence level.