A Rapid Multi-Modal Parameter Estimation Technique for LISA

The laser interferometer space antenna (LISA) will observe gravitational-wave(GW) signals from a wide range of sources, including massive black hole binaries (MBHBs). Although numerous techniques have been developed to perform Bayesian inference for LISA, they are often computationally expens-ive; analyses often take at least similar to 1 month on a single CPU, even when using accelerated techniques. Not only does this make it difficult to concurrently Analyse more than one GW signal, it also makes it challenging to rapidly pro-duce parameter estimates for possible electromagnetic follow-up campaigns. simple-pewas recently developed to produce rapid parameter estimates forGW signals observed with ground-based GW detectors. In this work, we extend simple-peto produce rapid parameter estimates for LISA sources, includ-ing the effects of higher order multipole moments. We show that simple-peinfers the source properties of massive black hole binaries in zero-noise atleast similar to 100xfaster than existing techniques;similar to 12 h on a single CPU. We fur-ther demonstrate that simple-pecan be applied before existing Bayesiantechniques to mitigate biases in multi-modal parameter estimation analyses of MBHBs.