TITLE:   GCN CIRCULAR
NUMBER:  23119
SUBJECT: Konus-Wind observation of GRB 180806A
DATE:    18/08/10 15:33:07 GMT
FROM:    Anastasia Tsvetkova at Ioffe Institute  <tsvetkova@mail.ioffe.ru>

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

The long-duration GRB 180806A
(Fermi GBM detection: Malacaria et al., GCN 23095)
triggered Konus-Wind at T0=81544.19 s UT (22:39:04.190).

The burst light curve shows a single pulse with a total duration of ~20 s.
The emission is seen up to ~1.2 MeV.

As observed by Konus-Wind, the burst
had a fluence of 2.92(-0.36,+0.41)x10^-5 erg/cm2,
and a 64-ms peak energy flux, measured from T0+5.712 s,
of 5.52(-1.59,+1.66)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(measured from T0 to T0+7.424 s)
is best fit in the 20 keV - 16 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.76(-0.14,+0.16),
the high energy photon index beta = -2.56(-0.79,+0.32),
the peak energy Ep = 352(-53,+59) keV,
chi2 = 90/94 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180806_T81544/

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