TITLE: GCN CIRCULAR NUMBER: 43772 SUBJECT: Konus-Wind detection of GRB 260212A DATE: 26/02/17 14:55:21 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 260212A (Fermi-GBM detection: The Fermi GBM team, GCN 43716; Neights and Meegan GCN 43740; Glowbug detection: Cheung et al., GCN 43719; SVOM-GRM detection: Zhang et al., GCN 43727; GECAM-B detection: Zhang et al., GCN 43736; AstroSat-CZTI detection: Salunke et al., GCN 43741; IPN triangulation: Kozyrev et al., GCN 43769) triggered Konus-Wind (KW) at T0=64149.637 s UT (17:49:09.637). The burst light curve shows multiple emission pulses in the interval from ~T0-0.5 s to ~T0+11 s. The emission is seen up to ~2 MeV. We also note a much weaker emission bump around T0+25 s, which is visible only below 80 keV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB260212_T64149/ As observed by Konus-Wind, the burst had the fluence of (6.81 ± 0.55)x10^-6 erg/cm^2 and the 64-ms peak energy flux, measured from T0 + 0.640 s, of (4.98 ± 0.40)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum of the burst (measured from T0 to T0+16.640 s) is best fitted 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 = -1.16 (-0.10, + 0.10) and Ep = 115(-7,+9) keV, chi^2 = 97/93 dof. Fitting this spectrum by a Band GRB function yields the same values of alpha and Ep, and only an upper limit on the high energy photon index beta of -2.7 The spectrum near the peak count rate (measured from T0 to T0+8.448 s) is best fitted in the 20 keV - 15 MeV range by a CPL model with alpha = -0.86 (-0.11, + 0.12)and Ep = 108(-8,+10) keV, chi^2 = 94/78 dof. Fitting this spectrum by a Band function yields the same values of alpha and Ep, and only an upper limit on the high energy photon index beta of -3.2 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/43772. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...