TITLE: GCN CIRCULAR NUMBER: 22553 SUBJECT: Konus-Wind observation of GRB 180326A DATE: 18/03/27 14:23:52 GMT FROM: Anna Kozlova at Ioffe Institute A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 180326A (IPN Triangulation: Hurley et al., GCN 22550) triggered Konus-Wind at T0=12367.064 s UT (03:26:07.064). The burst light curve shows a multipeaked structure which starts at ~T0-0.2 s and has a total duration of ~20.6 s. The emission is seen up to ~6 MeV. As observed by Konus-Wind, the burst had a fluence of 2.19(-0.30,+0.36)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+0.336 s, of 9.16(-2.36,+2.52)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+16.640 s) is best fit in the 20 keV - 6 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.55(-0.20,+0.24) and Ep = 767(-142,+200) keV (chi2 = 80/80 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.0 (chi2 = 80/79 dof) The spectrum near the maximum count rate (measured from T0+0.256 to T0+8.448 s) is best fit in the 20 keV - 6 MeV range by a power law with exponential cutoff model with alpha = -0.61(-0.20,+0.23) and Ep = 806(-151,+208) keV (chi2 = 85/80 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.6 (chi2 = 85/79 dof) The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB180326_T12367/ We note the MAXI J1820+070 activity seen in the waiting mode data. All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.