TITLE: GCN CIRCULAR NUMBER: 22548 SUBJECT: Konus-Wind observation of GRB 180316A DATE: 18/03/26 15:10:45 GMT FROM: Anastasia Tsvetkova at Ioffe Institute A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 180316A (Swift detection of a burst: Melandri et al., GCN 22500; Cummings et al., GCN 22512) triggered Konus-Wind at T0=17845.869 s UT (04:57:25.869). The burst light curve shows a single emission episode which starts at ~T0-13 s and has a total duration of ~29 s. The emission is seen up to ~1.2 MeV. As observed by Konus-Wind, the burst had a fluence of 1.43(-0.21,+0.38)x10^-5 erg/cm2, and a 64-ms peak energy flux, measured from T0+2.976 s, of 2.77(-1.16,+1.49)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+16.640 s) is best fit in the 20 keV - 1.2 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with  alpha = -1.23(-0.23,+0.27), and Ep = 439(-139,+424) keV (chi2 = 74/60 dof). Fitting by the GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -1.87 (chi2 = 74/59 dof). The spectrum near the peak count rate (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 2 MeV range by a power law with exponential cutoff model with  alpha = -1.19(-0.22,+0.26), and Ep = 498(-165,+498) keV (chi2 = 54/61 dof). Fitting by the GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -1.75 (chi2 = 53/60 dof). The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB180316_T17845/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.