Constraining possible $\gamma$-ray burst emission from GW230529 using Swift-BAT and Fermi-GBM

Understand

GW230529 is the first compact binary coalescence detected by the LIGO-Virgo-KAGRA collaboration with at least one component mass confidently in the lower mass-gap, corresponding to the range 3-5$M_{\odot}$.

• If interpreted as a neutron star-black hole merger, this event has the most symmetric mass ratio detected so far and therefore has a relatively high probability of producing electromagnetic (EM) emission.
• However, no EM counterpart has been reported.
• At the merger time $t_0$, Swift-BAT and Fermi-GBM together covered 100$\%$ of the sky.