GCN Circular 39386
Subject
Konus-Wind detection of GRB 250217C (short)
Event
Date
2025-02-20T14:18:00Z (a year ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
Via
Web form
D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia,
A. Tsvetkova, M. Ulanov, and T. Cline
on behalf of the Konus-Wind team, report:
The short-duration GRB 250217C
(Fermi-GBM detection: The Fermi GBM team, GCN 39357;
Smith, GCN 39367;
AstroSat-CZTI detection: Tembhurnikar et al., GCN 39359;
IPN triangulation: Kozyrev et al., GCN 39365;
SVOM-GRM detection: Wang et al., GCN 39369)
triggered Konus-Wind at T0=86086.280 s UT (23:54:46.280).
The burst light curve shows a multipeaked structure
which starts at ~T0 and has a total duration of ~0.3 s.
The emission is seen up to ~4 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB250217_T86086/
As observed by Konus-Wind, the burst
had a fluence of 2.76(-0.35,+0.38)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0+0.190 s,
of 2.38(-0.47,+0.49)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+0.256 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 = -0.27(-0.49,+0.70),
the high energy photon index beta = -1.93(-0.11,+0.09),
the peak energy Ep = 116(-26,+40) keV
(chi2 = 47/37 dof).
All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.