2024/07/04 by I. M. Romero-Shaw, Samir Goorachurn, Romero-Shaw, Isobel M. +4
Physics and Astronomy · #Astrophysical Phenomena and Observations #Relativity and Gravitational Theory #Cosmology and Gravitation Theories
paper · pdf · doi:10.48550/arxiv.2407.03869
Stellar-mass binary black holes may have circumbinary disks if formed through common-envelope evolution or within gaseous environments. Disks can drive binaries into wider and more eccentric orbits, while gravitational waves harden and circularise them. We combine cutting-edge evolution prescriptions for disk-driven binaries with well-known equations for gravitational-wave-driven evolution, and study the evolution of stellar-mass binary black holes. We find that binaries are driven by their disk to an equilibrium eccentricity, 0.2\lesssim eeq \lesssim0.5, that dominates their evolution. Once they transition to the GW-dominated regime their eccentricity decreases rapidly; we find that stellar-mass binary black holes with long-lived disks will likely be observed in LISA with detectable eccentricities ∼ 10-2 at 0.01 Hz, with the precise value closely correlating with the binary's initial mass ratio. This may lead stellar-mass binary black holes with CBDs observed in LISA to be confused with dynamically-formed binary black holes.