TITLE:   GCN CIRCULAR
NUMBER:  20625
SUBJECT: Konus-Wind observation of GRB 170206A
DATE:    17/02/07 21:17:17 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

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

The short-duration, hard-spectrum, bright GRB 170206A
(Fermi-GBM detection: von Kienlin and Roberts, GCN Circ. 20616;
Fermi-LAT detection: Fana Dirirsa et al., GCN Circ. 20617;
IPN triangulation: Hurley et al., GCN Circ. 20623)
triggered Konus-Wind at T0=39121.226 s UT (10:52:01.226).

The burst light curve shows a multipeaked structure
started at ~T0-0.2 s with a total duration of ~1.5 s.
The emission is seen up to ~15 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB170206_T39121/

As observed by Konus-Wind, the burst
had a fluence of 1.49(-0.15,+0.16)x10^-5 erg/cm2,
and a 16-ms peak flux, measured from T0+0.306 s,
of 3.30(-0.64,+0.66)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+1.280 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = 0.00(-0.20,+0.24),
the high energy photon index beta = -2.28(-0.18,+0.13),
the peak energy Ep = 260(-29,+33) keV
(chi2 = 58/61 dof)

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