[vsnet-grb-info 18229] Konus-Wind observation of GRB 160709A (short/hard)

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19677
SUBJECT: Konus-Wind observation of GRB 160709A (short/hard)
DATE:    16/07/10 13:15:15 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred at mail.ioffe.ru>

D. Frederiks, S. Golenetskii, R.Aptekar, P. Oleynik, M. Ulanov,
D. Svinkin, A. Tsvetkova, A.Lysenko, A. Kozlova, and T. Cline,
on behalf of the Konus-Wind team, report:

The short/hard GRB 160709A
(Fermi-LAT detection: Guiriec, et al., GCN Circ. 19675;
Fermi-GBM detection: Jenke, GCN Circ. 19676)
triggered Konus-Wind at T0=71345.896 s UT (19:49:05.896).

The light curve shows a short, hard pulse with a total duration
of ~0.4 s. The emission is seen up to ~8 MeV.

As observed by Konus-Wind, the burst had a fluence of
(1.5 ± 0.3)x10^-5 erg/cm2 and a 16-ms peak energy flux,
measured from T0, of (6.3 ± 0.9)x10^-5 erg/cm2
(both in the 20 keV - 10 MeV energy range).

The spectrum of the burst (measured from T0 to T0+0.256 s)
is best fit in the 20 keV - 10 MeV range by a cutoff power-law
(CPL) function with the following model parameters:
the photon index alpha = -0.51(-0.17,+0.19),
and the peak energy Ep = 2554(-509,+664) keV,
chi2 = 40.1/50 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep with only an upper limit on beta of -2.1,
chi2 = 39.8/49 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB160709_T71345/

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