Difference: GCNCIRCULAR21746 ( vs. 1)

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 G298048 (2017-08-17 12:41:04.446 UTC, hereafter T0; LIGO/Virgo Collaboration GCN Circ. 21509) coincident with Fermi GBM trigger 524666471 (Connaughton et al., GCN Circ. 21506, Goldstein et al., GCN Circ. 21528).

Using waiting-mode data within the interval T0 +/- 100 s, we found no significant (> 4 sigma) excess over the background in both KW detectors on temporal scales from 2.944 s to 100 s.

For the 2.944 s interval containing GBM trigger and the highest-probability localization region for the LIGO/Virgo G298048 (LVC, GCN Circ. 21513) we estimate an upper limit (90% conf.) on the 10 keV – 10 MeV fluence to 3.0x10^-7 erg/cm^2 for a burst lasting less than 2.944 s and having the spectrum reported by Goldstein et al. (an exponentially cut off power law, CPL, with alpha =-0.9 and Ep=128 keV). For a typical short GRB spectrum (CPL with alpha=-0.5 and Ep=500 keV), the limiting fluence is 6.9x10^-7 erg/cm^2 (10 keV – 10 MeV).

All the quoted values are preliminary.

-- ThomasKupfer - 29 Aug 2017