TITLE: GCN CIRCULAR NUMBER: 23859 SUBJECT: Konus-Wind observation of GRB 190203A DATE: 19/02/04 12:23:45 GMT FROM: Dmitry Frederiks at Ioffe Institute D. Frederiks, S. Golenetskii, R.Aptekar, A. Kozlova, A.Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The long GRB 190203A (Swift/BAT detection: Lien et al., GCN 23845) triggered Konus-Wind at T0=56630.443 s UT (15:43:50.443). The KW light curve shows a multi-peaked structure in the interval from T0-39 s to T0-58 s. The emission is seen up to ~4 MeV. As observed by Konus-Wind, the burst had a fluence of (4.9 ± 0.5)x10^-5 erg/cm2 and a 64-ms peak energy flux, measured from T0+20.352, of (3.5 ± 0.4)x10^-6 erg/cm2 (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum (measured from T0 to T0+57.344 s) is best fit in the 20 keV - 15 MeV range by a cutoff power-law (CPL) function with the following model parameters: the photon index alpha = -0.45(-0.11,+0.12), and the peak energy Ep = 314(-22,+25) keV, chi2 = 98/98 dof. Fitting this spectrum with the GRB (Band) function yields the same alpha and Ep, and only an upper limit on beta (<-2.7). The spectrum near the peak count rate (measured from T0+16.640 to T0+24.574 s) is best fit in the 20 keV - 15 MeV range by the CPL function with the following model parameters: the photon index alpha = -0.17(-0.16,+0.18), and the peak energy Ep = 348(-29,+34) keV, chi2 = 90/98 dof. Fitting this spectrum with the GRB (Band) function yields the same alpha and Ep, and only an upper limit on beta (<-2.5). The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB190203_T56630/ All the quoted errors are estimated at the 90% confidence level. All the presented results are preliminary.