[vsnet-grb-info 15313] Konus-Wind observation of GRB 140716A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16605
SUBJECT: Konus-Wind observation of GRB 140716A
DATE:    14/07/18 20:25:13 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, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:

A long duration GRB 140716A (Swift-BAT: Cummings, GCN 16596; GCN 16598;
Fermi-GBM: Jenke and Yu, GCN 16599) triggered Konus-Wind at
T0=37676.966 s UT (10:27:56.966).

The burst light curve shows three emission episodes, the first at ~T0, 
the second double pulse episode at ~T0+90 s, and the third weak at 
~T0+167 s. The total duration of the burst is ~170 s.
The emission is seen up to ~1 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB140716_T37676/

As observed by Konus-Wind, the burst
had a fluence of 9.4(-1.6,+2.2)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0+0.354 s,
of 2.8(-0.8,+1.1)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+114.944 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -1.09 (-0.38,+0.51)
and Ep = 157 (-41,+84) keV (chi2 = 60/58 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.2
(chi2 = 60/57 dof)

The spectrum near the maximum count rate
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model
with  alpha = -1.09 (-0.41,+0.68)
and Ep = 196 (-72,+174) keV (chi2 = 58/58 dof).

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