GCN Circular 32999
Subject
Konus-Wind detection of GRB 221124A
Date
2022-12-01T18:06:09Z (2 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 long-duration GRB 221124A
(CALET-CGBM detection: Sugita et al., GCN Circ. 32981;
Swift/BAT-GUANO detection: Tohuvavohu et al., GCN Circ. 32984;
GECAM-B detection: Huang et al., ATel 15777)
triggered Konus-Wind at T0=7224.17 s UT (02:00:24.170).
The burst light curve shows a multipeaked structure
which starts at ~T0-64 s and has a total duration of ~425 s.
The emission is seen up to 5 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB221124_T07224/
As observed by Konus-Wind, the burst
had a fluence of 4.71(-0.98,+1.92)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0-0.006 s,
of 2.17(-0.76,+0.82)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+360.704 s)
is best fit in the 20 keV - 5 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.80(-0.30,+0.38),
the high energy photon index beta = -2.96(-7.04,+0.70),
the peak energy Ep = 172(-35,+47) keV
(chi2 = 74/74 dof).
The spectrum near the maximum count rate
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.70(-0.36,+0.45)
and Ep = 275(-59,+106) keV (chi2 = 47/60 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.4
(chi2 = 47/59 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.