TITLE: GCN CIRCULAR NUMBER: 20402 SUBJECT: LIGO/Virgo G268556/GW170104: Lomonosov BDRG observations DATE: 17/01/09 07:57:14 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.V.Bogomolov, S.I.Svertilov, A.M.Amelushkin, V.O.Barinova, M.I.Panasyuk, A.V.Bogomolov, A.F.Iyudin, V.V.Kalegaev, D.Nguen, V.L. Petrov, I.V.Yashin, P.S.Kazarian, N.L.Dzhioeva, Physics Department, Skobel`tsyn Institute of Nuclear Physics, Lomonosov Moscow State University V. Lipunov, E.S. Gorbovskoy, N.Tyurina, D.Kuvshinov, M.Panchenko Lomonosov Moscow State University, Sternberg Astronomical Institute I. Park, J. Lee, S. Jeong Department of Physics, Sungkyunkwan University, Seobu-ro, Jangangu, Suwonsi, Korea At event time for G268556 the detectors BDRG-1 and BDRG-2 on-board Lomonosov were directed >60 degrees far from all regions present on LIGO probability map for G268556. BDRG-3 detector observed the southern high probability region directed to RA=25.8, Dec=-30.7. The Lomonosov satellite was located over South Africa at outer regions of SAA leading to high background. No burst-like events were observed, the 3 sigma upper limit for 1s-long GRB flux in 20-800 keV range is 2.5 cm-2*s-1. The time intervals when the region of maximal probability of GW source was in BDRG FOV on 04.01.2017 from 9h to 13h are 9:07-9:27, 9:33-9:47, 10:42-11:02, 11:07-11:24, 12:17-12:37, 12:42-12:59. No on-board GRB-triggers were generated at this time intervals. BDRG on-board triggers were generated 4 times during the time period from 10 hours before GW event to 10 hours after it (at 02:33:17, 0 4:12:19, 08:06:49 and 13:36:41).The significance of all these triggers do not exceed 9.5 sigma correspondent to the level of random events occurring ~10 times per day. The upper limit for 1s-GRB flux in 50-300 keV is 0.5 cm-2*s-1 equivalent to 1e-7 erg/cm2 for typical GRB spectra. This message can be cited.