TITLE: GCN CIRCULAR NUMBER: 7862 SUBJECT: Konus-Wind observation of GRB 080607 DATE: 08/06/08 15:49:55 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team report: The bright GRB 080607 (Swift-BAT trigger #313417: Mangano et al., GCN 7847, Stamatikos et al., GCN 7852) triggered Konus-Wind at T0=22043.336 s UT (06:07:23.336). The burst light curve consists of the main part, which shows a multipeaked structure with a duration of ~16 s, and the extended emission, which shows many weak pulses up to ~T0+85 s in the soft energy band (~18-70 keV). As observed by Konus-Wind the burst had a fluence of 8.93(-0.47, +0.52)x10^-5 erg/cm2, and a 16-ms peak flux measured from T0+7.168 s of (2.69 +/- 0.54)x10^-5 erg/cm2/s (both in the 20 keV - 4 MeV energy range). The time-integrated spectrum of the burst (from T0 to T0+84.48 s) can be fitted (in the 20 keV - 4 MeV range) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.08(-0.06, +0.07), and Ep = 419(-38, +46) keV (chi2 = 78.8/73 dof). Fitting by GRBM (Band) model yields: the low-energy photon index is alpha = -1.06(-0.08, +0.09), the high energy photon index beta < -2.28, the peak energy Ep = 394(-54, +58) keV (chi2 = 77.2/72 dof). The spectrum of the main part (from T0 to T0+18.944 s) can be fitted (in the 20 keV - 4 MeV range) by GRBM (Band) model for which: the low-energy photon index is alpha = -0.76(-0.06, +0.07), the high energy photon index beta = -2.57(-0.26, +0.18), the peak energy Ep = (348 +/- 27) keV (chi2 = 99.6/72 dof). The fluence of this part is (8.59 +/- 0.40)x10^-5 erg/cm2. All the quoted errors are at the 90% confidence level. Assuming z = 3.036 (Prochaska et al., GCN 7849) and a standard cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.27, Omega_\Lambda = 0.73, the isotropic energy release is E_iso = 1.87(-0.10, +0.11)x10^54 erg, the peak luminosity is (L_iso)_max = (2.27 +/- 0.46)x10^54 erg/s, and Ep_rest ~1600 keV. This isotropic energy release is one of the largest ever measured (the current record holder is GRB 990123 for which the isotropic energy release is ~2.8x10^54 erg), and this peak luminosity is the highest ever reported. The Konus-Wind light curve of this GRB is available at http://www.ioffe.rssi.ru/LEA/GRBs/GRB080607_T22043/