GCN Circular 31430
Subject
Konus-Wind detection of GRB 220107B
Event
Date
2022-01-10T19:42:50Z (4 years ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin,
A. Tsvetkova, M. Ulanov, and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration GRB 220107B
(Fermi-LAT detection: Arimoto et al., GCN 31409;
AstroSat CZTI detection: Suresh et al., GCN 31412;
Fermi-GBM observation: Veres and Meegan et al., GCN 31414)
triggered Konus-Wind at T0=68494.81 s UT (19:01:34.810).
The burst light curve shows a multipeaked structure
started at ~T0-1.2 s with a total duration of ~26.4 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/GRB220107_T68494/
As observed by Konus-Wind, the burst
had a fluence of 4.20(-0.78,+0.91)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+1.728 s,
of 8.07(-2.17,+2.27)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+32.768 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 = -0.73(-0.19,+0.27),
the high energy photon index beta = -2.18(-0.38,+0.22),
the peak energy Ep = 309(-65,+72) keV
(chi2 = 54/69 dof).
The spectrum near the maximum count rate
(measured from T0+0.256 to T0+8.192 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 = -0.58(-0.17,+0.20),
the high energy photon index beta = -2.21(-0.37,+0.21),
the peak energy Ep = 334(-56,+68) keV
(chi2 = 54/70 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.