[vsnet-grb-info 15137] Konus-Wind observation of GRB

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16429
SUBJECT: Konus-Wind observation of GRB 
DATE:    14/06/21 14:56:08 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val at mail.ioffe.ru>

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

A long-duration, very intense GRB 140616C (IPN triangulation: Hurley et 
al., GCN 16427) triggered Konus-Wind at T0=81966.864 s UT (22:46:06.864).

The burst light curve shows two separate multipeaked episodes: the first
from ~T0-6 s to ~T0+12 s and the second longer and brighter
from ~T0+68 s to ~T0+93 s. The total duration of the burst is ~105 s.
The emission is seen up to ~10 MeV.

As observed by Konus-Wind, the burst had a fluence
of 1.1(-0.08,+0.08)x10^-4 erg/cm2, and a 64-ms peak flux,
measured from T0+72.832 s, of 2.25(-0.16,+0.16)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+97.792 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -1.15 (-0.15,+0.19),
the high energy photon index beta = -2.37 (-0.13,+0.10),
the peak energy Ep = 129 (-12,+13) keV,
chi2 = 94/84 dof.

The spectrum near the peak count rate
(measured from T0+65.792 to T0+81.408 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -1.05 (-0.13,+0.13),
the high energy photon index beta = -2.37 (-0.14,+0.09),
the peak energy Ep = 169 (-15,+20) keV,
chi2 = 114/97 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB140619_T81966/

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