TITLE: GCN CIRCULAR NUMBER: 32258 SUBJECT: Konus-Wind detection of GRB 220623A DATE: 22/06/24 12:32:17 GMT FROM: Dmitry Frederiks at Ioffe Institute 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 220623A (Swift detection: Sbarufatti et al., GCN Circ. 32243; AstroSat-CZTI detection: Gopalakrishnan et al., GCN Circ 32246; AGILE detection: Ursi et al., GCN Circ 32247) triggered Konus-Wind (KW) at T0=25447.564 s UT (07:04:07.564). The burst light curve shows a bright, double-peaked structure which starts at ~T0-0.2 s and has a total duration of ~15 s. A weaker emission in visible in the KW lc until ~T0+50 s. The emission at the bright phase of the event is seen up to ~2.5 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB220623_T25447/ As observed by Konus-Wind, the burst had a fluence of (2.5 ± 0.3)x10^-5 erg/cm^2 and a 64-ms peak energy flux, measured from T0 + 0.064 s, of (8.8 ± 0.8)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum (measured from T0 to T0+49.408 s) is best fit in the 20 keV - 15 MeV range by a power law with exponential cutoff (CPL) model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.13(-0.11,+0.12) and Ep = 869(-224,+363) keV (chi2 = 93/98 dof). Fitting this spectrum by a Band function yields the same values of alpha and Ep, and an upper limit on the high energy photon index beta of -2.6 (chi2 = 93/97 dof). The spectrum near the peak count rate (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 15 MeV range by a CPL function with alpha = -0.82(-0.09,+0.10) and Ep = 910(-136,+177) keV (chi2 = 86/98 dof). Fitting this spectrum by a Band function yields the same values of alpha and Ep, and an upper limit on the high energy photon index beta of -2.9 (chi2 = 86/97 dof). All the quoted errors are estimated at the 90% confidence level. All the presented results are preliminary.