A rapid multi-modal parameter estimation technique for LISA

Abstract 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 expensive; analyses often take at least ∼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 produce parameter estimates for possible electromagnetic follow-up campaigns. simple-pe was recently developed to produce rapid parameter estimates for GW signals observed with ground-based GW detectors. In this work, we extend simple-pe to produce rapid parameter estimates for LISA sources, including the effects of higher order multipole moments. We show that simple-pe infers the source properties of massive black hole binaries in zero-noise at least <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:mrow><mml:mo>∼</mml:mo></mml:mrow><mml:mn>100</mml:mn><mml:mo>×</mml:mo></mml:mrow></mml:math> faster than existing techniques; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:mrow><mml:mo>∼</mml:mo></mml:mrow><mml:mn>12</mml:mn></mml:mrow></mml:math> h on a single CPU. We further demonstrate that simple-pe can be applied before existing Bayesian techniques to mitigate biases in multi-modal parameter estimation analyses of MBHBs.