[vsnet-grb-info 6978] Konus-Wind observation of GRB 081126

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8562
SUBJECT: Konus-Wind observation of GRB 081126
DATE:    08/11/27 14:52:48 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val at mail.ioffe.ru>

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 081126 (Margutti et al., GCN 8554, Sato et al. GCN 8557) 
triggered Konus-Wind at T0=77649.857 s UT (21:34:09.857).

The burst light curve shows a precursor at ~T0-20 s and two main pulse 
at ~T0-3 s and ~T0+28 s with a total duration of ~60 s.

As observed by Konus-Wind the burst
had a fluence of 9.91(-1.46, +1.57)x10^-6 erg/cm2,
and a 256-ms peak flux measured from T0+1.808 s
of (1.65 +/- 0.36)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+41.216 s) is well 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 = -0.82(-0.26, +0.32) ,
and Ep = 315(-71, +123)  keV (chi2 = 68.0/61 dof).
Fitting by GRBM (Band) model yields only an upper limit on
the high energy photon index: beta < -2.16.

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/GRB081126_T77649/