TITLE: GCN CIRCULAR NUMBER: 27394 SUBJECT: LIGO/Virgo S200316bj: Upper limits from Fermi-GBM Observations DATE: 20/03/17 03:24:48 GMT FROM: Joshua Wood at MSFC/Fermi-GBM J. Wood (NASA/MSFC) reports on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group For S200316bj and using the initial bayestar.fits.gz,1 skymap, Fermi-GBM was observing 33.4% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of the LIGO/Virgo detection of GW trigger S200316bj (GCN 27388). An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around merger time, and also identified no counterpart candidates. Part of the LVC localization region is behind the Earth for Fermi, located at RA=58.3, Dec=19.5 with a radius of 67.2 degrees. We therefore set upper limits on impulsive gamma-ray emission for the LVC localization region visible to Fermi at merger time. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV, weighted by GW localization probability (in units of 10^-7 erg/s/cm^2): Timescale Soft Normal Hard ------------------------------------ 0.128 s: 1.7 2.5 5.3 1.024 s: 0.4 0.8 1.8 8.192 s: 0.2 0.3 0.5 Assuming the median luminosity distance of 1222 Mpc from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^49 erg/s): Timescale Soft Normal Hard ------------------------------------ 0.128s: 4.7 6.2 22. 1.024s: 1.1 2.0 7.5 8.192s: 0.5 0.7 2.2