Difference: GCNCIRCULAR20775 (1 vs. 2)

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=20 event G275697 (2017-02-27 18:57:31.375 UTC, hereafter T0; LIGO/VIRGO=20 Collaboration GCN Circ. 20763).

No triggered KW event happened from ~5 days before to more than 10 hours after T0. We found no significant (> 5 sigma) detection on temporal=20 scales from 2.944 s to 100 s using waiting mode data from both KW=20 detectors S1 and S2 within the interval T0 =1B+/- 100 s.

We estimate an upper limit (90% conf.) on the 10 keV E2=80=93 10 MeV fluen ce to 7.8x10^-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=0B=3D-0.5 and Ep=3D500 keV). For a typical long GRB spectrum (the Ban= d=20 function with alpha=3D-1, beta=3D-2.5, and Ep=3D300 keV), the corresponding= =20 limiting peak flux is 2.7x10^-7 erg/cm^2/s (10 keV - 10 MeV, 2.944 s scale).

All the quoted values are preliminary.

-- ThomasKupfer - 28 Feb 2017