[vsnet-grb-info 20726] Konus-Wind observation of GRB 180620A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22824
SUBJECT: Konus-Wind observation of GRB 180620A
DATE:    18/06/22 15:25:50 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin at mail.ioffe.ru>

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

The long-duration GRB 180620A
(Swift-BAT detection: Evans et al., GCN Cric. 22798)
triggered Konus-Wind at T0=30906.173 s UT (08:35:06.173).

The burst light curve shows a multi-peaked structure
which starts at ~T0-6.6 s and has a total duration of ~16 s.
The emission is seen up to ~2 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180620_T30906/

As observed by Konus-Wind, the burst
had a fluence of 9.80(-1.02,+1.74)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0+7.504 s,
of 2.69(-0.82,+0.94)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+8.448 s)
is best fit in the 20 keV - 4 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -1.19(-0.14,+0.16),
the high energy photon index beta = -3.09(-6.91,+0.63),
the peak energy Ep = 164(-24,+29) keV
(chi2 = 70/75 dof).

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