TITLE: GCN CIRCULAR NUMBER: 24724 SUBJECT: LIGO/Virgo S190602aq: Upper limits from Fermi-GBM Observations DATE: 19/06/03 00:35:20 GMT FROM: Colleen A. Wilson at NASA/MSFC/NSSTC C.A. Wilson-Hodge and C. M. Hui (NASA/MSFC) report on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group For S190602aq and using the initial bayestar.fits skymap, Fermi-GBM was observing 67.3% 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 S190602aq (GCN 24717). 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 = 148.4 and Dec = -10.9 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:      4.3 7.5 17.0 1.0 s:      1.1 3.4 8.2 10  s:    0.27 0.63 1.7 Assuming the median luminosity distance of 797 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:     5.0          8.0 30.0     1.0 s:     1.3          3.6 14.5     10  s:   0.3 0.7 3.0