[vsnet-grb-info 24758] Konus-Wind observation of GRB 200120A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26857
SUBJECT: Konus-Wind observation of GRB 200120A
DATE:    20/01/22 18:18:59 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred at mail.ioffe.ru>

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

The long GRB 200120A (Fermi GBM localization: GCN 26831;
IPN triangulation: Hurley et al., GCN 26856;
Insight-HXMT/HE detection: Zheng et al., GCN 26840)
triggered Konus-Wind at T0=83096.553 s UT (23:04:56.553).

The burst light curve shows a mult-peaked pulse
which starts at ~T0-5 s and has a total duration of ~12 s.
The emission is seen up to ~2 MeV.

As observed by Konus-Wind, the burst
had a fluence of 8.2(-0.7,+0.8)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0+3.368 s,
of 4.0(-0.5,+0.4)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+8.448 s)
is best fit in the 20 keV - 15 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -1.12(-0.15,+0.17)
and Ep = 221(-32,+47) keV (chi2 = 105/98 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.3
(chi2 =105/97 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB200120_T83096/

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