TITLE: GCN CIRCULAR NUMBER: 16374 SUBJECT: Konus-Wind observation of GRB 140606B DATE: 14/06/10 12:20:20 GMT FROM: Anastasia Tsvetkova at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 140606B (Fermi-GBM detection: Burns, GCN 16319; IPN triangulation: Golenetskii et al., GCN 16369) triggered Konus-Wind at T0=11510.769 s UT (03:11:50.769). The burst light curve shows a single pulse with a duration of ~8 s. The emission is seen up to ~5 MeV. As observed by Konus-Wind, the burst had a fluence of 6.6(-0.5,+0.5)x10^-6 erg/cm2, and a 64-ms peak flux, measured from T0+0.752 s, of 2.9(-0.7,+0.7)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+8.448 s) is best fit in the 20 keV - 5 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.60(-0.18,+0.20), and Ep = 254(-27,+33) keV (chi2 = 78/73 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.9 (chi2 = 78/72 dof). Assuming the redshift z=0.384 (Perley et al., GCN 16365) 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 2.5(-0.2,+0.2)x10^51 erg, the peak luminosity L_iso is 1.5(-0.4,+0.4)x10^51 erg/s, and the rest-frame peak energy, Ep,i, is 352(-37,+46) keV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB140606_T11510/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.