2025/12/18 by Thomas Kupfer, Kupfer, Thomas, Simone Scaringi +25
Physics and Astronomy · #Astronomy and Astrophysical Research #FOS: Physical sciences #Gamma-ray bursts and supernovae #High Energy Astrophysical Phenomena (astro-ph.HE) #Instrumentation and Methods for Astrophysics (astro-ph.IM) #Pulsars and Gravitational Waves Research #Solar and Stellar Astrophysics (astro-ph.SR)
paper · doi:10.48550/arxiv.2512.16988
openalex publication_date 2025/12/18 · openalex created_date 2025/12/23 · openalex updated_date 2026/07/28
Ultracompact Galactic binaries with orbital periods below an hour are among the strongest persistent gravitational-wave (GW) sources in the mHz band and will constitute the dominant population detected by the Laser Interferometer Space Antenna (LISA). Tens of thousands are predicted to be individually resolved, with a substantial fraction bright enough for electromagnetic (EM) follow-up. This opens an unprecedented multi-messenger window on compact binary evolution, tidal interactions, mass transfer, and the progenitors of Type Ia supernovae. We highlight key science enabled by joint GW + EM constraints and emphasize the critical need for rapid, high-cadence spectroscopic capabilities in the 2040s. In particular, the most compact (<10 min) binaries detected by LISA will require read-noise-free, zero-dead-time spectroscopic facilities, potentially realized through coordinated arrays of telescopes with time-staggered exposures, to measure radial velocities, tidal heating signatures, and orbital evolution with the precision needed for transformative multi-messenger studies.