TITLE: GCN CIRCULAR NUMBER: 24513 SUBJECT: LIGO/Virgo S190512at: Fermi GBM Observations DATE: 19/05/13 01:19:59 GMT FROM: Suraj Poolakkil at UAH S. Poolakkil (UAH) and C.M. Hui (NASA/MSFC) report on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group: For S190512at, and using the updated BAYESTAR skymap, Fermi-GBM was observing 34.7% 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 S190512at (GCN 24503). 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 = 308.1 and Dec = -3.6 with a radius of 67.2 degrees. We therefore set upper limits on impulsive gamma-ray emission. Using the representative soft, normal, and hard GRB-like spectral templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV, weighted by the remaining visible GW localization probability (in units of erg/s/cm^2): Timescale soft norm hard ----------------------------------------------- 0.128 s: 2.4e-07 4.3e-07 1.0e-06 1.024 s: 5.3e-08 1.1e-07 2.5e-07 8.192 s: 2.3e-08 2.3e-08 8.0e-08 Assuming the median luminosity distance of ~1331 Mpc from the GW detection, we estimate intrinsic luminosity upper limits of (0.8-7.9)E49 erg/s for the soft template, (0.7-12.7)E49 erg/s for the normal template, and (3.9-49.3)E49 erg/s for the hard template over the 1 keV-10 MeV energy range.