TITLE: GCN CIRCULAR NUMBER: 30838 SUBJECT: Konus-Wind observation of the recent SGR 1935+2154 activity DATE: 21/09/13 17:56:37 GMT FROM: Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru> A. Ridnaia, S. Golenetskii, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: Since the last KW GCN on the ongoing SGR 1935+2154 activity (Ridnaia et al., GCN 30803) the instrument triggered on four bright bursts from the source. The following is a list of the Konus-Wind triggers with preliminary estimates of the burst fluences and peak fluxes. ------------------------------------------------------------------ # Date T0(KW) s UT Fl* PF** ------------------------------------------------------------------ 1 20210911 54406.825 s UT(15:06:46.825) 5.38 +/-0.15 22.6 +/-1.6 2 20210911 61274.025 s UT(17:01:14.025) 7.84 +/-0.21 18.5 +/-1.4 3 20210912 24677.185 s UT(06:51:17.185) 4.96 +/-0.14 26.6 +/-1.7 4 20210912 28904.121 s UT(08:01:44.121) 1.25 +/-0.02 17.0 +/-1.4 ------------------------------------------------------------------ * - Fluence (20-500 keV) in units of 1e-6 erg/cm2 ** - Peak Flux (20-500 keV) on 16-ms time scale in units of 1e-6 erg/cm2/s The time-averaged spectra of the bursts are well fit in the 20 - 200 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with the following parameters: ------------------------------------------------------------------ # T100 Tbeg-Tend alpha Ep(keV) chi2/dof ------------------------------------------------------------------ 1 0.392 0 - 0.256 0.47(-0.32,+0.33) 42(-2,+2) 30/20 2 1.243 0 - 8.448 0.40(-0.37,+0.39) 37(-2,+1) 36/28 3 0.452 0 - 0.256 0.20(-0.35,+0.37) 38(-2,+2) 17/19 4 1.600 0 - 8.448 -0.10(-0.21,+0.22) 35(-1,+1) 43/29 ------------------------------------------------------------------ The emission in all bursts is seen up to ~200 keV. The Konus-Wind light curves of the bursts are available at http://www.ioffe.ru/LEA/SGRs/210911_T54406/ http://www.ioffe.ru/LEA/SGRs/210911_T61274/ http://www.ioffe.ru/LEA/SGRs/210912_T24677/ http://www.ioffe.ru/LEA/SGRs/210912_T28904/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.