TITLE: GCN CIRCULAR NUMBER: 21500 SUBJECT: LIGO/Virgo G297595: Konus-Wind observations DATE: 17/08/16 20:17:43 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: Konus-Wind (KW) was observing the whole sky at the time of the LIGO/Virgo event G297595 (2017-08-14 10:30:43.527 UTC, hereafter T0; LIGO/Virgo Collaboration GCN Circ. 21474). No triggered KW event happened from ~4 day before and up to ~1.3 days after T0. The closest waiting-mode event was ~1.1 days after T0. Using waiting-mode data within the interval T0 +/- 100 s, we found no significant (> 5 sigma) excess over the background in both KW detectors on temporal scales from 2.944 s to 100 s. We estimate an upper limit (90% conf.) on the 10 keV – 10 MeV fluence to 5.9x10^-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 2.2x10^-7 erg/cm^2/s (10 keV - 10 MeV, 2.944 s scale). All the quoted values are preliminary.