TITLE: GCN CIRCULAR NUMBER: 26205 SUBJECT: LIGO/Virgo S191109d: Upper limits from Fermi-GBM Observations DATE: 19/11/09 05:51:52 GMT FROM: Peter Veres at UAH P. Veres (UAH) reports on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group: For S191109d and using the initial BAYESTAR skymap, Fermi-GBM was observing 87.2% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of S191109d (GCN 26202). 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= 320.9, Dec= 12.1 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 normal hard -------------------------------------- 0.128 s: 6.3 9.5 23 1.024 s: 1.5 2.3 5.5 8.192 s: 0.50 0.76 1.4 Assuming the median luminosity distance of 1810 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: 38 52 210 1.024s: 9.2 13 50 8.192s: 3.1 4.1 13