Global analysis of the gravitational wave signal from Galactic binaries

Galactic ultracompact binaries are expected to be the dominant source of gravitational waves in the milli-Hertz frequency band. Of the tens of millions of Galactic binaries with periods shorter than an hour, it is estimated that a few tens of thousand will be resolved by the future Laser Interferometer Space Antenna (LISA). The unresolved remainder will be the main source of "noise" between 1 and 3 mHz. Typical Galactic binaries are millions of years from merger, and consequently their signals will persist for the duration of the LISA mission. Extracting tens of thousands of overlapping Galactic signals and characterizing the unresolved component is a central challenge in LISA data analysis, and a key contribution to arriving at a global solution that simultaneously fits for all signals in the band. Here we present an end-to-end analysis pipeline for Galactic binaries that uses transdimensional Bayesian inference to develop a time-evolving catalog of sources as data arrive from the LISA constellation.