TITLE: GCN CIRCULAR NUMBER: 17587 SUBJECT: Konus-Wind observation of GRB 150314A DATE: 15/03/15 12:48:21 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, very intense GRB 150314A (Swift-BAT trigger #634795: Hagen et al., GCN 17572; Cummings et al., GCN 17581; Fermi-LAT detection: Axelsson et al., GCN 17576; Fermi-GBM observation: Yu, GCN 17579) triggered Konus-Wind at T0=17691.727 s UT (04:54:51.727). The KW light curve shows a bright multi-peaked pulse with a duration of ~14 s. The emission is visible up to ~10 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB150314_T17691/ As observed by Konus-Wind, the burst had a fluence of 9.1(-0.4,+0.4)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+1.344 s, of 2.2(-0.1,+0.1)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum (measured from T0 to T0+12.288 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 = -0.79 (-0.04,+0.04), the high energy photon index beta = -2.91 (-0.28,+0.18), the peak energy Ep = 350 (-17,+17) keV, chi2 = 142/97 dof. The spectrum near the peak count rate (measured from T0+0.256 to T0+2.048 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 = -0.37 (-0.08,+0.09), the high energy photon index beta = -2.81 (-0.27,+0.18), the peak energy Ep = 348 (-27,+27) keV, chi2 = 134/94 dof. Assuming the redshift z=1.758 (de Ugarte Postigo et al., GCN 17583) and a standard cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.27, and Omega_Lambda = 0.73, we estimate the following rest-frame parameters: the isotropic energy release E_iso is ~6.9x10^53 erg, the peak luminosity L_iso is ~4.6x10^53 erg/s, and the rest-frame peak energy of the time-integrated spectrum, Ep,i, is ~965 keV. All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.