[vsnet-grb-info 11506] Konus-Wind observation of GRB 120129A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  12905
SUBJECT: Konus-Wind observation of GRB 120129A
DATE:    12/01/31 10:18:12 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 long intense GRB 120129A
(localized by IPN: Golenetskii et al., GCN 12904)
triggered Konus-Wind at T0=50148.403s UT (13:55:48.403).
The observation is performed against very high and variable
background count rate caused by solar charged particles.

The burst light curve shows two bright partly overlapped pulses.
A total duration of the burst is ~4 s.
The emission is seen up to ~5 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB120129_T50148/

As observed by Konus-Wind the burst
had a fluence of (2.7 ± 0.7)x10-5 erg/cm2,
and a 16-ms peak flux, measured from T0+0.672 s,
of (3.3 ± 1.0)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+3.328 s)
is best fitted in the 20 keV - 5 MeV range
with the GRB (Band) model, for which:
the low-energy photon index alpha = -0.76 (-0.09, +0.09),
the high energy photon index beta = -2.9 ( <-2.3),
the peak energy Ep = 326(-38, +52) keV,
chi2 = 66.5/76 dof.

The spectrum at the maximum count rate
(measured from T0+0.512 to T0+0.768 s) is best fitted
is best fitted in the 20 keV - 5 MeV range
with the GRB (Band) model, for which:
the low-energy photon index alpha = -0.51 (-0.19, +0.21),
the high energy photon index beta = -2.3 (-1.4, +0.3),
the peak energy Ep = 317(-66, +92) keV,
chi2 = 54.2/61 dof.


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