TITLE: GCN CIRCULAR NUMBER: 16223 SUBJECT: Konus-Wind observation of GRB 140506A DATE: 14/05/08 13:33:01 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.Lyssenko, and T. Cline on behalf of the Konus-Wind team, report: A long-duration GRB 140506A (Swift-BAT trigger 598284: Gompertz et al., GCN 16214; Markwardt et al., GCN 16218; Fermi-GBM detection: Jenke, GCN 16220) triggered Konus-Wind at T0=76059.098 s UT (21:07:39.098). The light curve shows two bursting episodes: a narrow, double-peaked pulse from ~T0-1.1 s to ~T0+1.6 s, followed by a broad, weak, soft pulse from ~T0+49 s to ~T0+63 s A total duration of the burst is ~64 s. The emission is seen up to ~7 MeV. As observed by Konus-Wind, the burst had a fluence of 6.6(-1.6,+1.8)x10^-6 erg/cm2, and a 64-ms peak flux, measured from T0+0.640 s, of 6.2(-1.9,+2.5)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the first bursting episode (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 18 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -1.3 (-0.2,+0.3), the high energy photon index beta = -2.3 (-7.7,+0.4), the peak energy Ep = 187 (-59,+90) keV, chi2 = 94/97 dof. The time-averaged spectrum of the second bursting episode (measured from T0+49.408 to T0+65.792 s) is best fit in the 20 keV - 18 MeV range by a simple power-law function with the photon index 2.06(-0.13,+0.14), chi2 = 98/98 dof. Assuming the redshift z=0.889 (Fynbo et al., GCN 16217) 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 ~1.4x10^52 erg, the peak luminosity L_iso is ~2.5x10^52 erg/s, and the rest-frame peak energy, Ep,i, is ~350 keV (as derived from the spectrum of the first episode). The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB140506_T76059/ All the quoted errors are at the 1 sigma confidence level. All the quoted values are preliminary.