TITLE: GCN CIRCULAR NUMBER: 32500 SUBJECT: Konus-Wind detection of GRB 220826A DATE: 22/08/29 17:46:51 GMT FROM: Dmitry Frederiks at Ioffe Institute fred@mail.ioffe.ru
D. Frederiks, A.Lysenko, A. Ridnaya, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report:
The long GRB 220826A (Swift detection: Caputo et al., GCN 32484; Fermi GBM observation: Veres & Meegan, GCN 32495) was detected by Konus-Wind (KW) in the waiting mode.
A Bayesian block analysis of the KW waiting mode data in the 20-400 keV band reveals a >10 sigma count rate increase in the interval from T0-0.525 s to T0+37.747 s where T0 = T0(BAT) = 11:55:21.742 UT.
The KW light curve of this burst is available at http://www.ioffe.ru/LEA/GRBs/GRB220826A/
Modeling a time-integrated spectrum of the burst by a power law with exponential cutoff (CPL) model dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields alpha = -0.48 (-0.22, + 0.25) and Ep = 113(-4,+4) keV. In the 10 keV -10 MeV band, standard for the KW analysis, the burst fluence is (2.53 ± 0.29)x10^-6 erg/cm^2 and the 2.944 s peak energy flux is (2.86 ± 0.18)x10^-7 erg/cm^2/s.
All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary.