GCN Circular 32157
Subject
Konus-Wind detection of GRB 220528A
Event
Date
2022-06-01T09:20:20Z (4 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
D. Svinkin, D. Frederiks, A.Ridnaia, A.Lysenko,
A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The short-duration GRB 220528A
(Fermi-GBM detection: Fermi GBM Team, GCN Circ. 32147;
Mangan et al., GCN Circ. 32155;
Swift/BAT-GUANO detection: Raman et al., GCN Circ. 32148;
IPN triangulation: Svinkin at al., GCN Circ. 32156)
triggered Konus-Wind at T0=22370.380 s UT (06:12:50.380).
The burst light curve shows a multipeaked structure,
which starts at T0-0.1 s and has a total duration of ~0.7 s.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB220528_T22370/
As observed by Konus-Wind, the burst
had a fluence of 1.85(-0.03,+0.54)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0+0.034 s,
of 7.88(-1.57,+2.77)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
Since the main fraction of the burst emission was detected
before the trigger, the spectral analysis was performed using
the KW 3-channel light curve data.
Modelling the KW 3-channel time-integrated spectrum
(measured from T0-0.402 s to T0+0.296 s)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep),
yields alpha = -0.06(-0.32,+0.38) and Ep = 542(-78,+118) keV.
All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.