TITLE: GCN CIRCULAR NUMBER: 24928 SUBJECT: LIGO/Virgo S190630ag: Upper limits from Fermi-GBM Observations DATE: 19/07/01 00:42:27 GMT FROM: Cori Fletcher at USRA C.A. Wilson-Hodge (NASA/MSFC) & R. Hamburg (UAH) on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group For S190630ag and using the initial bayestar.fits skymap, Fermi-GBM was observing 87.7% 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 S190630ag (GCN 24922). 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 = 169.7 and Dec = -3.8 with a radius of 67.5 degrees. We therefore set upper limits on impulsive gamma-ray emission. 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 (in units of 10^-7 erg/s/cm^2): Timescale Soft Normal Hard ------------------------------------ 0.1 s: 4.4 5.8 17.0 1.0 s: 1.1 1.9 4.4 10 s: 0.47 0.56 1.0 Assuming the median luminosity distance of 1059 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 ------------------------------------ 0.1 s: 9.2 10. 53. 1.0 s: 2.3 3.6 14. 10 s: 1.0 1.1 3.1