TITLE: GCN CIRCULAR NUMBER: 31086 SUBJECT: Konus-Wind detection of GRB 211107B DATE: 21/11/16 14:29:21 GMT FROM: Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru> D. Svinkin, S. Golenetskii, D. Frederiks, M. Ulanov, A. Tsvetkova, A. Lysenko, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 211107B (Swift-BAT detection: Tohuvavohu, GCN Circ. 31057) triggered Konus-Wind at T0=62836.647 s UT (17:27:16.647). The burst light curve shows the initial pulse, which starts at ~T0-3.7 s and has a total duration of ~24 s, followed by a weaker emission seen up to T0+205 s. The emission is seen up to ~1 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB211107_T62836/ As observed by Konus-Wind, the burst had a fluence of 8.95(-1.76,+1.88)x10^-6 erg/cm2, and a 64-ms peak flux, measured from T0-0.108 s, of 1.42(-0.68,+0.69)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The spectrum of the initial pulse (measured from T0 to T0+16.640 s) is best fit in the 20 keV - 2 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.88(-0.40,+0.47) and Ep = 152(-26,+41) keV (chi2 = 51/56 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.7 (chi2 = 51/55 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.