GCN Circular 32286
Subject
Konus-Wind detection of GRB 220624A
Event
Date
2022-06-28T12:44:56Z (4 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin,
A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The long GRB 220624A (Fermi-GBM detection: Fermi GBM Team, GCN 32256; Lesage & Meegan, GCN Circ 32269;
AGILE detection: Ursi et al., GCN Circ 32259;
Swift/BAT-GUANO detection outside the coded FOV: Tohuvavohu et al., GCN Circ 32263;
IPN triangulation: Kozyrev et al., GCN 32265;
CALET-CGBM detection: Akaike et al., GCN Circ 32272)
triggered Konus-Wind (KW) at T0=10712.946 s UT (02:58:32.946).
The burst light curve shows three major emission episodes.
The first episode lasts from ~T0-3 s to ~T0+54 s,
the second - from ~T0-135 s to ~T0+168 s,
and the third - from ~T0-291 s to ~T0+365 s.
The total duration of the burst is ~370 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/GRB220624_T10712/
As observed by Konus-Wind, the burst had
a fluence of (3.15 �� 0.49)x10^-4 erg/cm^2 and
a 64-ms peak energy flux, measured from T0 + 5.760 s,
of (2.22 �� 0.15)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum (measured from T0 to T0+340.224 s)
is best fit in the 20 keV - 15 MeV range
by a GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.89 (-0.14,+0.17),
the high energy photon index beta = -2.11 (-0.28,+0.17),
the peak energy Ep = 379 (-71,+86) keV,
chi2 = 65/97 dof.
The spectrum near the peak count rate (measured from T0 to T0+14.336 s)
is best fit in the 20 keV - 15 MeV range
by a GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.51 (-0.06,+0.06),
the high energy photon index beta = -2.17 (-0.06,+0.06),
the peak energy Ep = 439 (-25,+27) keV,
chi2 = 89/97 dof.
All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.