TITLE:   GCN CIRCULAR
NUMBER:  11425
SUBJECT: Konus-Wind observation of GRB 101123A
DATE:    10/11/27 11:10:20 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin,
P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf
of the Konus-Wind team, report:

The long bright GRB 101123A (Fermi/GBM
trigger 312245496 / 101123952: Guiriec, GCN 11423;
localized by IPN: Hurley et al., GCN 11424)
triggered Konus-Wind at T0=82338.387s UT (22:52:18.387)

The burst light curve contains three main bursting
episodes with a total duration of ~120 s.
The emission is seen up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB101123_T82338/

As observed by Konus-Wind the burst
had a fluence of (2.5 ± 0.3)x10-4 erg/cm2,
and a 64-ms peak flux, measured from T0+9.984s,
of (1.9 ± 0.3)x10-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(measured from T0 to T0+118.272 s) is best fit
in the 20 keV - 10 MeV range by the GRB (Band) model,
for which:
the low-energy photon index alpha = -0.9 (+/-0.1),
the high energy photon index beta = -2.1 (-0.2, +0.1),
the peak energy Ep = 449(-66, +83)keV (chi2 = 100/84 dof).

The spectrum at the maximum count rate
(measured from T0+9.984 to T0+11.776 s) is best fit
in the 20 keV - 10 MeV range by a power law
with exponential cutoff model, for which
alpha = -0.81(+/-0.08),
and Ep = 574(-52, +60) keV (chi2 = 69/62 dof).
Fitting this spectrum by the GRB (Band) model
yields to the same values of alpha and Ep, with
only an upper limit for beta (< -3.3)

All the quoted results are preliminary.
All the quoted errors are at the 90% confidence level.