GCN Circular 32849
Subject
Konus-Wind detection of GRB 221023A
Event
Date
2022-10-25T15:49:28Z (3 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 221023A
(AGILE detection: Ursi et al., GCN 32825;
Fermi-GBM observation: Fermi GBM team, GCN 32826;
Dunwoody et al., GCN 32845;
Fermi-LAT detection: Pillera et al., GCN 32831)
triggered Konus-Wind at T0=74492.216 s UT (20:41:32.216).
The burst light curve shows a multipeaked structure,
which starts at ~T0-0.5 s and has a total duration of ~145.9 s.
The emission is seen up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB221023_T74492/
As observed by Konus-Wind, the burst
had a fluence of 6.60(-0.35,+0.35)x10^-4 erg/cm2,
and a 64-ms peak flux, measured from T0+18.928 s,
of 3.84(-0.52,+0.52)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+149.248 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -1.05(-0.03,+0.03),
the high energy photon index beta = -2.27(-0.17,+0.13),
the peak energy Ep = 760(-64,+68) keV
(chi2 = 128/98 dof).
The spectrum near the maximum count rate
(measured from T0+18.688 to T0+19.200 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.66(-0.12,+0.15),
the high energy photon index beta = -2.32(-0.41,+0.22),
the peak energy Ep = 707(-147,+184) keV
(chi2 = 47/55 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.