he Search for Gamma-ray Emission from Fermi-GBM and Swift-BAT in Coincidence with LVK O3 Events

Since the detection of the binary neutron star merger (GW170817) in coincidence with the short gamma ray burst (GRB 170817A), the search for electromagnetic emission from similar events has been an imperative part of multi-messenger astronomy. Therefore, we searched Fermi Gamma-ray Burst Monitor (Fermi-GBM) and Swift Burst Alert Telescope (Swift-BAT) rate data around the GW event times presented by the LIGO\Virgo\Kagra Collaboration (LVK) in the third observing run (O3). O3 was the most sensitive gravitational wave search to date. Using Fermi-GBM on-board triggers and two sub-threshold searches, the Targeted and the Untargeted Search, as well as rate date from Swift-BAT, we determine whether there are any coincident gamma-ray transients associated with the O3 events. To date, no new joint events beyond GRB 170817A and GW170817 have been found. Using both the Fermi-GBM Targeted Search and the Swift-BAT search, we place upper limits on the associated gamma-ray luminosity for the events and present joint upper limit skymaps. Using the lack of electromagnetic emission binary black hole (BBH) mergers, we begin to constrain theoretical models of how such emission is produced.