[vsnet-grb-info 14711] Konus-Wind observation of GRB 140320D

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16025
SUBJECT: Konus-Wind observation of GRB 140320D
DATE:    14/03/21 17:15:12 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin at mail.ioffe.ru>

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

A very intense, long-duration, hard-spectrum GRB 140320D (IPN 
triangulation: K. Hurley et al., GCN 16023) triggered Konus-Wind at 
T0=73298.804 s UT (20:21:38.804).

The burst light curve shows a bright, double-peaked pulse with a total
duration of ~50 s. The emission is seen up to ~10 MeV.

As observed by Konus-Wind, the burst had
a fluence of (2.1 +/- 0.1)x10^-4 erg/cm2, and
a 64-ms peak flux, measured from T0+15.456 s, of (6.7 +/- 0.7)x10^-5 
erg/cm2/s (both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum (measured from T0 to T0+45.568 s) is best fit 
in the 20 keV - 10 MeV range by the GRB (Band) function with the 
following model parameters:
the low-energy photon index alpha = -0.83 (-0.03,+0.03),
the high energy photon index beta = -2.75 (-0.32,+0.20),
the peak energy Ep = 575 (-30,+32) keV,
chi2 = 100/87 dof.

The spectrum near the maximum count rate
(measured from T0+15.360 to T0+15.872 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.30 (-0.11,+0.13),
the high energy photon index beta = -2.59 (-0.62,+0.30),
the peak energy Ep = 655 (-89,+102) keV,
chi2 = 82/56 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB140320_T73298/

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