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GCN Circular 32614

Subject
Konus-Wind detection of GRB 220930A
Date
2022-10-02T17:09:27Z (a year 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 220930A
(Swift-BAT detection: Cenko et al., GCN 32603,
Barthelmy et al., GCN 32612;
AstroSat-CZTI detection: Gopalakrishnan et al., GCN 32613)
triggered Konus-Wind at T0=40312.503 s UT (11:11:52.503).

The burst light curve shows a multipeaked structure
which starts at ~T0-1.5 s and has a total duration of ~76.0 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/GRB220930_T40312/

As observed by Konus-Wind, the burst
had a fluence of 1.78(-0.64,+0.98)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+0.960 s,
of 5.39(-2.28,+2.15)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+73.984 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 = -0.06(-1.06,+1.43),
the high energy photon index beta = -2.41(-0.51,+0.46),
the peak energy Ep = 198(-58,+181) keV
(chi2 = 91/98 dof).

The spectrum near the maximum count rate
(measured from T0 to T0+8.448 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 = -0.38(-0.56,+0.66),
the high energy photon index beta = -2.25(-1.42,+0.23),
the peak energy Ep = 215(-52,+121) keV
(chi2 = 97/96 dof).

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
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