GCN Circular 33349
Subject
Konus-Wind detection of GRB 230217A
Event
Date
2023-02-19T12:10:55Z (3 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
D. Svinkin, D. Frederiks, M. Ulanov, A. Tsvetkova,
A. Lysenko, A. Ridnaia, and T. Cline
on behalf of the Konus-Wind team, report:
The short-duration GRB 230217A
(Fermi-GBM detectin: The Fermi-GBM team, GCN Circ. 33338;
Swift-BAT detection: Moss et al., GCN Circ. 33339;
CALET-GBM detection: Torii et al., GCN Circ. 33342;
AGILE-MCAL detection: Casentini et al., GCN Circ. 33343)
triggered Konus-Wind at T0=78786.119 s UT (21:53:06.119).
The burst light curve shows a multi-peaked structure
which starts at ~T0-0.2 s and has a total duration of ~0.9 s.
The emission is seen up to ~6 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB230217_T78786/
As observed by Konus-Wind, the burst
had a fluence of 2.74(-0.35,+0.39)x10^-5 erg/cm2,
and a 16-ms peak flux, measured from T0+0.128 s,
of 9.45(-1.84,+1.94)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+8.448 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.81(-0.13,+0.14)
and Ep = 1367(-240,+309) 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 <-2.7
(chi2 = 105/97 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.