[vsnet-grb-info 6534] Konus-Wind observation of GRB 080825B

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8142
SUBJECT: Konus-Wind observation of GRB 080825B
DATE:    08/08/27 13:26:45 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 most intense part of the GRB 080825B localized by SuperAGILE 
(Evangelista et al., GCN 8133) triggered Konus-Wind
at T0=64012.487 s UT (17:46:52.487).

The burst light curve shows a weak emission starting at ~T0-70s,
the main multipeaked part (from ~T0-5s to ~T0+15s), and an extended 
emission seen up to ~T0+40s.

As observed by Konus-Wind the burst
had a fluence of 7.81(-0.70, +0.83)x10^-6 erg/cm2,
and a 256-ms peak flux measured from T0-0.080 s
of 1.21(-0.31, +0.32)x10^-6 erg/cm2/s
(both in the 20 keV - 1 MeV energy range).

The spectrum of the most intense part
(from T0 to T0+16.640 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 = -1.13(-0.36, +0.40),
and Ep = 72(-9, +11) keV (chi2 = 40.0/51 dof).
Fitting by GRBM (Band) model yields:
the low-energy photon index is alpha = -1.05(-0.38, +0.56),
the high energy photon index beta < -2.52,
the peak energy Ep = 71(-9, +11) keV (chi2 = 38.8/50 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/GRB080825_T64012/