TITLE: GCN CIRCULAR NUMBER: 16673 SUBJECT: Konus-Wind observation of GRB 140808A DATE: 14/08/09 14:54:50 GMT FROM: Dmitry Svinkin 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: A long-duration GRB 140808A (Fermi-GBM detection: Zhang, GCN Circ. 16669) triggered Konus-Wind at T0=3239.264 s UT (00:53:59.264). The burst light curve shows two emission episodes, the first, reported in GCN 16669, from ~T0-1.9 s to ~T0+3.6 s, and the second, from ~T0+303 s to ~T0+336 s. The second episode is also seen in the INTEGRAL (SPI-ACS) data but it can't be unambiguously attributed to the GRB by the triangulation, so far. The total duration of the burst is ~338 s. The emission is seen up to ~5 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB140808_T03239/ As observed by Konus-Wind, the first episode had a fluence of 3.12(-0.30,+0.33)x10^-6 erg/cm2, and a 64-ms peak flux, measured from T0+0.312 s, of 1.6(-0.4,+0.4)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the first episode (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 = -0.95 (-0.26,+0.29) and Ep = 127 (-18,+25) keV (chi2 = 91/78 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.6 (chi2 = 90/77 dof) The second episode had a fluence of 4.2(-1.2,+4.0)x10^-6 erg/cm2, in the 20 keV - 10 MeV energy range. The time-averaged spectrum of this episode (measured from T0+303.36 to T0+336.128 s) is best fit in the 20 keV - 5 MeV range by the power law with exponential cutoff model with alpha = -1.22 (-0.37,+0.48) and Ep = 376 (-158,+1558) keV (chi2 = 82/88 dof). Assuming the second episode is related to the GRB the total fluence is 7.3(-1.2,+4.0)x10^-6 erg/cm2. From the redshift z=3.29 (Gorosabel et al., GCN Circ. 16671) 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 ~1.7x10^53 erg, the peak luminosity L_iso is ~3.8x10^52 erg/s. All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.