TITLE: GCN CIRCULAR NUMBER: 43592 SUBJECT: Konus-Wind detection of GRB 260128A / EP260128a DATE: 26/02/01 16:47:41 GMT 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-duration GRB 260128A/EP260128a (Einstein Probe detection: Zhow et al., GCN 43549; Fermi-GBM Sub-Threshold Detection: Ravasio et al., GCN 43556) was detected by Konus-Wind (KW) in the waiting mode at T0=T0(KW)~23:40:00 UTC. A Bayesian block analysis of the KW data in the 20-1500 keV band reveals a >10 sigma count rate increase in the interval from ~T0-101 s to ~T0+61 s. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB260128A/ The time-integrated spectrum of the burst (measured from from ~T0-101 s to ~T0+61 s) is best described in the 20 - 1500 keV range by a power law with exponential cutoff (CPL) model with alpha = -0.93 ± 0.99 and Ep = (103 ± 16) keV. The spectrum near the peak count rate (measured from ~T0-4 s to T0+14 s) is best described by a CPL model with alpha = -1.26 ± 0.30 and Ep = (178 ± 31) keV. The total burst fluence is (6.12 ± 2.89)x10^-6 erg/cm^2, and the 2.944 s peak energy flux, measured from T0+2.082 s, is (1.57 ± 0.44)x10^-7 erg/cm^2 (both in the 20 - 1500 keV energy range). All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/43592. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...