TITLE: GCN CIRCULAR NUMBER: 18073 SUBJECT: Konus-Wind observation of GRB 150725A DATE: 15/07/27 09:11:27 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko, and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 150725A (Masumitsu et al., GCN Circ. 18062) triggered Konus-Wind at T0=31454.410 s UT (08:44:14.410), ~15 s before the MAXI trigger. The KW light curve measured in the triggered mode shows multiple bright pulses in the interval from ~T0-0.5 s to ~T0+60 s. The emission is visible up to ~10 MeV. As observed by Konus-Wind, the burst had a fluence of 1.55(-0.10,+0.09)x10^-4 erg/cm2, and a 64-ms peak flux, measured from T0+51.456 s, of 1.35(-0.23,+0.17)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum (measured from T0 to T0+58.112 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 = -0.84 (-0.07,+0.08), the high energy photon index beta = -2.32 (-0.13,+0.10), the peak energy Ep = 326 (-24,+28) keV, chi2 = 125/97 dof. The spectrum near the peak count rate (measured from T0+51.200 to T0+58.112 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 = -0.77 (-0.23,+0.26), the high energy photon index beta = -2.29 (-0.52,+0.18), the peak energy Ep = 270 (-53,+86) keV, chi2 = 92/97 dof. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB150725_T31454/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.