[vsnet-grb-info 6817] Konus-Wind observation of GRB 081025

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8412
SUBJECT: Konus-Wind observation of GRB 081025
DATE:    08/10/26 15:33:49 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 Swift-BATSS GRB 081025 (Copete et al., GCN 8409) triggered
Konus-Wind at T0=30186.316 s UT (08:23:06.316).

The burst light curve shows a multipeaked structure with a total 
duration of ~25 s.

As observed by Konus-Wind the burst
had a fluence of 5.37(-0.82, +0.96)x10^-6 erg/cm2,
and a 256-ms peak flux measured from T0-0.224 s
of 8.90(-2.62, +2.75)x10^-7 erg/cm2/s
(both in the 20 keV - 1 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+24.832 s) is well 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 = -0.67(-0.33, +0.43) ,
and Ep = 222(-46, +81)  keV (chi2 = 55.5/60 dof).
Fitting by GRBM (Band) model yields only an upper limit on
the high energy photon index: beta < -2.07.

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/GRB081025_T30186/