TITLE: GCN CIRCULAR NUMBER: 26185 SUBJECT: LIGO/Virgo S191105e: Upper limits from Fermi-GBM Observations DATE: 19/11/06 18:57:48 GMT FROM: Adam Goldstein at Fermi-GBM, USRA A. Goldstein (USRA) reports on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group For S191105e and using the initial BAYESTAR skymap, Fermi-GBM was observing 77.5% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of S191105e (GCN Circ. 26182). 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=315.6, Dec=21.5 with a radius of 67.5 degrees. We therefore set upper limits on impulsive gamma-ray emission for the LVC localization region visible to GBM 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 norm hard -------------------------------------- 0.128 s: 4.1 6.9 14. 1.024 s: 1.3 2.1 4.7 8.192 s: 0.3 0.6 1.6 Assuming the median luminosity distance of 1168 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 norm hard -------------------------------------- 0.128 s: 10. 16. 53. 1.024 s: 3.3 4.8 18. 8.192 s: 0.8 1.4 6.1