TITLE: GCN CIRCULAR NUMBER: 14575 SUBJECT: Konus-Wind observation of GRB 130505A DATE: 13/05/05 19:19:22 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 very intense GRB 130505A (Swift-BAT trigger #555136: Cannizzo et al., GCN 14564) triggered Konus-Wind (K-W) at T0=30147.038s UT (08:22:27.038). The K-W light curve shows a bright pulse with a duration of ~5s followed by a weaker decaying emission out to ~T0+30s with a slight increase in the count rate at ~T0+15s. The emission is seen up to ~10 Mev. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB130505_T30147/ As observed by Konus-Wind, the main phase of the burst had a fluence of (3.13 ± 0.06)x10^-4 erg/cm2 and a 64-ms peak flux, measured from T0+2.496 s, of (6.9 ± 0.3)x10^-5 erg/cm2/s (both in the 20 - 1200 keV energy range). The time-averaged spectrum (measured from T0 to T0+21.248 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 = -0.69 ± 0.04, the high energy photon index beta = -2.03 ± 0.03, the peak energy Ep = 631 ± 31 keV, chi2 = 113/92 dof. The spectrum at the maximum count rate (measured from T0+2.304 to T0+2.816 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 = -0.31 ± 0.09, the high energy photon index beta = -2.26 ± 0.07, the peak energy Ep = 604 ± 49 keV, chi2 = 105/90 dof. Assuming z=2.27 (Tanvir et al., GCN 14567) and a standard cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.27, and Omega_Lambda = 0.73, the isotropic energy release E_iso is ~3.8x10^54 erg, the peak luminosity (L_iso)_max is ~2.7x10^54 erg/s, and the rest-frame peak energy Ep,i = 2030 keV All the quoted errors are estimated at the 1 sigma confidence level.