[vsnet-grb-info 8478] Konus-Wind observation of GRB 091003A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9994
SUBJECT: Konus-Wind observation of GRB 091003A
DATE:    09/10/05 10:14:24 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, M. Ulanov, D. Svinkin, and T. Cline on behalf of the
Konus-Wind team, report:

The long bright GRB 091003A (Fermi-GBM trigger 276237347 / 091003191:
Rau, GCN 9983) localized by Fermi-LAT (McEnery et al., GCN 9985)
triggered Konus-Wind at T0=16543.801 s UT (04:35:43.801).

The burst light curve shows a multipeaked structure with a total
duration of ~23 s.

As observed by Konus-Wind the burst
had a fluence of 3.44(-0.19, +0.20)x10^-5 erg/cm2,
and a 16-ms peak flux measured from T0+18.592 s
of (1.68 +/- 0.32)x10^-5 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+26.880 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 = -1.04 +/- 0.06,  and
Ep = 381(-36, +44) keV (chi2 = 58.4/61 dof).
Fitting by GRB (Band) model yields the same alpha and Ep,
and only an upper limit on the high energy
photon index: beta < -2.22 (chi2 = 56.2/60 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.ru/LEA/GRBs/GRB091003_T16543/