[vsnet-grb-info 6753] Konus-Wind observation of GRB 081001

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8353
SUBJECT: Konus-Wind observation of GRB 081001
DATE:    08/10/10 14:05:56 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 GRB 081001 localized by SuperAGILE
(Lazzarotto et al., GCN 8305) triggered Konus-Wind
at T0=76663.649 s UT (21:17:43.649).

The burst light curve shows a main pulse with a duration of ~6 s 
followed by a much weaker pulse at T0+~30 s with a duration of ~10 s.

As observed by Konus-Wind the burst
had a fluence of 9.70(-0.86, +1.00)x10^-6 erg/cm2,
and a 64-ms peak flux measured from T0+0.688 s
of 5.63(-1.12, +1.16)x10^-6 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).

The spectrum of the main pulse
(from T0 to T0+8.448 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 = -0.99(-0.18, +0.21),
and Ep = 239(-32, +45) keV (chi2 = 54.9/61 dof).
Fitting by GRBM (Band) model yields:
the low-energy photon index is alpha = -0.95(-0.21, +0.48),
the high energy photon index beta < -2.14,
the peak energy Ep = 227(-70, +52) keV (chi2 = 54.1/60 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/GRB081001_T76663/