Tidal heating effects in binary black hole mergers
Phys. Rev. D 113, 104011 – Published 7 May, 2026
DOI: https://doi.org/10.1103/wydq-hzvb
Abstract
A black hole binary approaching merger undergoes changes in its inspiral rate as energy and angular momentum are lost from the orbits into the horizons. This effect strengthens as the black holes come closer. We use numerical relativity data to model this so-called tidal heating in the strong-gravity regime. We also present a frequency-domain approximant for nonspinning black hole binaries that accounts for tidal heating effects up to the merger frequency. The approximant includes horizon parameters that characterize the nature of the compact objects. This model serves two main purposes: (1) leveraging the stronger effects of tidal heating near merger, it allows for more robust tests for the presence of black holes compared to the tests with inspiral-only analytical waveforms, and (2) by applying this model to a binary black hole baseline waveform that incorporates tidal heating, one can construct more accurate point-particle waveforms free from the finite-size effects of the component objects. We discuss its ramifications in modeling binary neutron star systems.
