TITLE: GCN CIRCULAR NUMBER: 33586 SUBJECT: Konus-Wind detection of GRB 230405B DATE: 23/04/07 11:34:01 GMT FROM: Anna Ridnaia at Ioffe Institute A.Ridnaia, D. Frederiks, A.Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The long-duration GRB 230405B (Fermi-GBM detection: The Fermi GBM team, GCN 33570; Wood & Meegan, GCN 33583; Swift-BAT detection: Page et al., GCN 33571; AstroSat CZTI detection: Navaneeth et al., GCN 33575; AGILE detection: Casentini et al., GCN 33585) triggered Konus-Wind at T0=71884.77 s UT (19:58:04.770). The burst light curve shows a single pulse, which starts at ~T0-6.1 s and has a total duration of ~10.7 s. The emission is seen up to ~2 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB230405_T71884/ As observed by Konus-Wind, the burst had a fluence of 2.24(-0.23,+0.27)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+1.088 s, of 9.76(-1.97,+2.26)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.37(-0.26,+0.30), the high energy photon index beta = -2.75(-0.64,+0.31), the peak energy Ep = 184(-20,+23) keV (chi2 = 101/91 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.