[vsnet-grb-info 14237] Konus-Wind observation of GRB 131126A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15551
SUBJECT: Konus-Wind observation of GRB 131126A
DATE:    13/11/29 17:01:35 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred at mail.ioffe.ru>

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

The short-duration, hard-spectrum, bright GRB 131126A
(IPN Triangulation: Golenetskii et al., GCN 15550)
triggered Konus-Wind at T0=14048.270 s UT (03:54:08.270).

The burst light curve shows a pulse with a duration of ~140 ms.
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/GRB131126_T14048/

As observed by Konus-Wind, the burst
had a fluence of (2.1 ± 0.2)x10-6 erg/cm2,
and a 16-ms peak flux, measured from T0+0.016,
of (2.4 ± 0.2)x10-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum
(measured from T0 to T0+0.128 s)
is best fit, in the 20 keV - 15 MeV range,
by a cutoff power law with the following model parameters:
the photon index alpha = -0.43 ± 0.14
and the peak energy Ep = 633 ± 85 keV,
chi2 = 46.2/65 d.o.f.

The spectrum near the maximum count rate
(measured from T0 to T0+0.064 s)
is best fit, in the 20 keV - 15 MeV range,
by a cutoff power law with the following model parameters:
the photon index alpha = -0.20 ± 0.20
and the peak energy Ep = 680 ± 100 keV,
chi2 = 40.6/60 d.o.f.


All the quoted results are preliminary.