[vsnet-grb-info 26414] Konus-Wind detection of GRB 200920B

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28514
SUBJECT: Konus-Wind detection of GRB 200920B
DATE:    20/09/27 19:50:30 GMT
FROM:    Anna Ridnaia at Ioffe Institute  <ridnaia at mail.ioffe.ru>

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

The short-duration GRB 200920B
(AGILE/MCAL detection: Ursi et al., GCN Circ. 28464;
IPN triangulation: Ridnaia et al., GCN Circ. 28467)
triggered Konus-Wind at T0=71814.617 s UT (19:56:54.617).

The burst light curve shows a multi-peaked structure
which started at ~T0-0.368 s and had a total duration of ~0.37 s.

The K-W light curve of this burst is available at
http://www.ioffe.ru/LEA/GRBs/GRB200920_T71814/

As observed by Konus-Wind, the burst had a fluence of
3.12(-0.61,+0.94)x10^-6 erg/cm2 and a 16-ms peak flux,
measured from ~T0-0.260 s, of 1.74(-0.52,+0.65)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Since the bulk of the burst emission was detected before
the trigger, the spectral analysis was performed using
the KW 3-channel light curve data.

Modelling the K-W 3-channel spectrum of the burst
(measured from T0-0.368 s to T0)
by the cutoff power law yields the following model parameters:
the photon index alpha = 0.15(-0.51,+0.95),
and the peak energy Ep = 935(-241,+401) keV.

All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.