TITLE: GCN CIRCULAR NUMBER: 20973 SUBJECT: IceCube-170321A: Konus-Wind upper limits DATE: 17/04/03 13:48:59 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: Using Konus-Wind (KW) waiting mode data, we have performed a search for a gamma-ray transient around the time of the cosmic neutrino candidate IceCube-170321A (2017-03-21 07:32:20.69 UT, hereafter T0; Blaufuss, GCN 20929). In the interval T0 +/- 1000 s we estimate an upper limit (90% conf.) on the 10 keV – 10 MeV fluence to ~6.6x10^-7 erg/cm^2 for a burst lasting less than 2.944 s and having a typical KW short GRB spectrum (an exponentially cut off power law with alpha =-0.5 and Ep=500 keV). For a typical long GRB spectrum (the Band function with alpha=-1, beta=-2.5, and Ep=300 keV), the corresponding limiting peak flux is ~2.3x10^-7 erg/cm^2/s (10 keV - 10 MeV, 2.944 s scale). All the quoted values are preliminary.