LISA Data Analysis: Challenges & Opportunities

The analysis of LISA data will encounter numerous novel challenges brought on by the huge number of astrophysical sources and the presence of multiple populations in the detector's sensitivity band. With the data stream containing of order ten thousand resolvable Galactic double white-dwarf systems, a stochastic foreground of many unresolvable Galactic binaries, transient signals over days to potentially months from coalescing massive black-hole binaries, extreme mass-ratio inspirals that may flex our understanding of gravity, and echoes of signals from the early Universe, this represents a diverse menagerie that could confound traditional approaches. Tackling these challenges will require the detector's noise and all signals from all source populations to be simultaneously searched for within a "global fit" framework. There are analogies here with techniques currently being employed by pulsar timing arrays, which simultaneously search over all pulsar noise and gravitational-wave processes at scales of several hundred parameter dimensions. But LISA presents a much higher trans-dimensional problem that will need efficient computational methods and high-performance accelerations to achieve the full mission potential and the resulting curation of a source catalog.