TITLE: GCN CIRCULAR NUMBER: 19244 SUBJECT: Konus-Wind observation of GRB 160325A DATE: 16/03/29 13:44:26 GMT FROM: Anastasia Tsvetkova at Ioffe Institute A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks, P. Oleynik, M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 160325A (Swift-BAT trigger #680436: Sonbas, Lien & Page, GCN 19222; Fermi GBM detection: Roberts, GCN 19224; Fermi-LAT detection: Axelsson et al., GCN 19227) triggered Konus-Wind at T0=25162.835 s UT (06:59:22.835). The burst light curve shows two emission episodes, a total duration of the burst (80-360 keV) is ~45 s. The emission is seen up to ~1.5 MeV. As observed by Konus-Wind, the burst had a fluence of 1.73(-0.12,+0.14)x10^-5 erg/cm2, and a 64-ms peak energy flux, measured from T0+10.304 s, of 3.04(-1.04,+1.08)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum of the burst (measured from T0 to T0+49.408 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) with alpha = -0.93(-0.14,+0.15), and Ep = 214(-23,+31) keV (chi2 = 69/60 dof). Fitting by the GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.45 (chi2 = 69/59 dof). The spectrum near the peak count rate (measured from T0 to T0+16.640 s) is best fit in the 20 keV - 2 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.76(-0.15,+0.18), the high energy photon index beta = -2.47(-0.59,+0.26), the peak energy Ep = 207(-26,+32) keV, chi2 = 70/57 dof. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB160325_T25162/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.