TITLE: GCN CIRCULAR NUMBER: 8694 SUBJECT: Konus-Wind observation of GRB 081221 DATE: 08/12/22 11:05:55 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik, D. Svinkin, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team report: The long GRB 081221 (Hoversten et al., GCN 8687) triggered Konus-Wind at T0=58874.915 s UT (16:21:14.915). The burst light curve shows two multipeaked pulses with a total duration of ~40 s. As observed by Konus-Wind the burst had a fluence of (2.28 +/- 0.07)x10^-5 erg/cm2, and a 256-ms peak flux measured from T0+19.824 s of (1.75 +/- 0.16)x10^-6 erg/cm2/s (both in the 20 keV - 1 MeV energy range). The time-integrated spectrum of the burst (from T0 to T0+39.424 s) can be fitted (in the 20 keV-1 MeV range) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.91(-0.14, +0.15), and Ep = (83 +/- 4) keV (chi2 = 67.4/51 dof). Fitting by GRB (Band) model yields the same alpha and Ep, and only an upper limit on the high energy photon index: beta < -3.48 (chi2 = 67.4/50 dof). Thus, it is a bright and soft GRB. All the quoted errors are at the 90% confidence level. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB081221_T58874/