[vsnet-grb-info 12236] Konus-Wind observation of GRB 120811B

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13621
SUBJECT: Konus-Wind observation of GRB 120811B
DATE:    12/08/11 13:28:20 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred at 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 short-duration hard GRB 120811B
(IPN localization: Golenetskii at al., GCN 13620)
triggered Konus-Wind at T0=01231.575s UT (00:20:31.575)

The light curve shows a double pulse,
a total duration of the burst is ~0.33 s.
The emission is seen up to ~6 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB120811_T01231/

As observed by Konus-Wind the burst
had a fluence of 4.6(-0.9,+1.0)x10-6 erg/cm2,
and a 16-ms peak flux, measured from T0,
of 2.8(-0.6,+0.7)x10-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The spectrum of the burst (measured from T0 to T0+0.256 s)
is best fit in the 20 keV - 7 MeV range
by a power law with exponential cutoff model, for which
alpha = -0.14 (-0.28, +0.35),
and Ep = 1130(-230, +310) keV,
chi2 = 13.6/24 dof.

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