TITLE: GCN CIRCULAR NUMBER: 8042 SUBJECT: Konus-Wind observation of GRB 080727B DATE: 08/07/28 12:43:57 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 long GRB 080727B (Swift-BAT trigger #318101: Immler et al., GCN 8022, Baumgartner et al., GCN 8030) triggered Konus-Wind at T0=29609.825 s UT (08:13:29.825). The burst light curve shows two multipeaked pulses with a total duration of ~9 s. As observed by Konus-Wind the burst had a fluence of 9.46(-0.84, +0.98)x10^-6 erg/cm2, and a 64-ms peak flux measured from T0+6.080 s of 5.14(-0.10, +0.11)x10^-6 erg/cm2/s (both in the 20 keV - 2 MeV energy range). The time-integrated spectrum of the burst (from T0 to T0+8.448 s) is well be fitted (in the 20 keV - 2 MeV range) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.85(-0.18, +0.16), and Ep = 282(-37, +52) keV (chi2 = 56.6/60 dof). Fitting by GRBM (Band) model yields: the low-energy photon index is alpha = -0.73(-0.24, +0.29), the high energy photon index beta < -2.08, the peak energy Ep = 242(-48, +69) keV (chi2 = 54.8/59 dof). All the quoted errors are at the 90% confidence level. The Konus-Wind light curve of this GRB is available at http://www.ioffe.rssi.ru/LEA/GRBs/GRB080727_T29609/