TITLE: GCN CIRCULAR NUMBER: 19851 SUBJECT: Konus-Wind observation of GRB 160820A DATE: 16/08/23 11:00:14 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, S. Golenetskii, R.Aptekar, D. Frederiks, P. Oleynik, M. Ulanov, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline on behalf of the Konus-Wind team, report: The short-duration, hard-spectrum GRB 160820A (IPN triangulation: Svinkin et al., GCN 19850) triggered Konus-Wind at T0=42855.115 s UT (11:54:15.115). The burst light curve shows a single pulse with a total duration of ~0.2 s. As observed by Konus-Wind, the burst had a fluence of 7.54(-0.86,+0.94)x10^-7 erg/cm2 and a 16-ms peak flux, measured from T0-0.058 s, of 5.63(-1.50,+1.52)x10^-6 erg/cm2/s (both in the 20 - 1000 keV energy range). Since a major fraction of the burst counts was accumulated before the trigger, the spectral analysis was performed using the KW 3-channel light curve data. Modeling the 3-channel time-integrated spectrum (measured from T0-0.158 s to T0+0.074 s) by the cutoff power law yields the following model parameters: the photon index alpha=0.87(-0.78,+2.13), and the peak energy Ep=383(-67,+73) keV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB160820_T42855/ All the quoted errors are at the 68% confidence level. All the quoted values are preliminary.