Missed opportunities: GRB 211211A and the case for continual gravitational-wave coverage with a single observatory

Understand

Gamma-ray burst GRB 211211A may have been the result of a neutron star merger at $\approx350$ Mpc.

• However, none of the LIGO-Virgo detectors were operating at the time.
• We show that the gravitational-wave signal from a \grb-like binary neutron star inspiral in the next LIGO-Virgo-KAGRA observing run (O4) would be below the conventional detection threshold, however a coincident gamma-ray burst observation would provide necessary information to claim a statistically-significant multimessenger observation.
• We calculate that with O4 sensitivity, approximately $11\%$ of gamma-ray bursts within 600 Mpc will produce a confident association between the gravitational-wave binary neutron star inspiral signature and the prompt gamma-ray signature.