TITLE: GCN CIRCULAR NUMBER: 26857 SUBJECT: Konus-Wind observation of GRB 200120A DATE: 20/01/22 18:18:59 GMT FROM: Dmitry Frederiks at Ioffe Institute D. Frederiks, S. Golenetskii, R. Aptekar, A. Lysenko, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline on behalf of the Konus-Wind team, report: The long GRB 200120A (Fermi GBM localization: GCN 26831; IPN triangulation: Hurley et al., GCN 26856; Insight-HXMT/HE detection: Zheng et al., GCN 26840) triggered Konus-Wind at T0=83096.553 s UT (23:04:56.553). The burst light curve shows a mult-peaked pulse which starts at ~T0-5 s and has a total duration of ~12 s. The emission is seen up to ~2 MeV. As observed by Konus-Wind, the burst had a fluence of 8.2(-0.7,+0.8)x10^-6 erg/cm2, and a 64-ms peak flux, measured from T0+3.368 s, of 4.0(-0.5,+0.4)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum of the burst (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 15 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.12(-0.15,+0.17) and Ep = 221(-32,+47) keV (chi2 = 105/98 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.3 (chi2 =105/97 dof). The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB200120_T83096/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.