TITLE: GCN CIRCULAR NUMBER: 27022 SUBJECT: LIGO/Virgo S200208q: Upper limits from Fermi-GBM Observations DATE: 20/02/08 22:20:42 GMT FROM: Suraj Poolakkil at UAH S. Poolakkil (UAH) reports on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group. For S200208q and using the bayestar.fits.gz,1 skymap, Fermi-GBM was observing 95.4% 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 S200208q (GCN 27014). 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=306.6, Dec=17.6 with a radius of 67.3 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 norm hard -------------------------- 0.128 s: 7.3 9.9 17. 1.024 s: 2.3 2.9 6.0 8.192 s: 0.6 0.9 2.2 Assuming the median luminosity distance of 2900 Mpc from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^50 erg/s): Timescale Soft Normal Hard ------------------------------------ 0.128s: 11.6 13.7 39.8 1.024s: 3.6 4.0 14.0 8.192s: 1.0 1.4 5.1