2022MNRAS.509.3957Y

The Advanced LIGO and Virgo gravitational-wave observatories have opened a new window with which to study the inspiral and mergers of binary compact objects. These observations are most powerful when coordinated with multimessenger observations. This was underlined by the first observation of a binary neutron star merger GW170817, coincident with a short gamma-ray burst, GRB170817A, and the identification of the host galaxy NGC 4993 from the optical counterpart AT2017gfo. Finding the fast-fading optical counterpart critically depends on the rapid production of a sky map based on LIGO/Virgo data. Currently, a rapid initial sky map is produced, followed by a more accurate, high-latency, ≳12 h sky map. We study optimization choices of the Bayesian prior and signal model, which can be used alongside other approaches such as reduced order quadrature. We find these yield up to a 60 per cent reduction in the time required to produce the high-latency localization for binary neutron star mergers.