Astro2020 Decadal Science White Paper: Gravitational Wave Survey of Galactic Ultra Compact Binaries

Understand

Ultra-compact binaries (UCBs) are systems containing compact or degenerate stars with orbital periods less than one hour.

• Tens of millions of UCBs are predicted to exist within theGalaxy emitting gravitational waves (GWs) at mHz frequencies.
• Combining GW searches with electromagnetic (EM) surveys like Gaia and LSST will yield a comprehensive, multimessenger catalog of UCBs in the galaxy.
• Joint EM and GW observations enable measurements of masses, radii, and orbital dynamics far beyond what can be achieved by independent EM or GW studies.