Sharp Signals of Boson Clouds in Black Hole Binary Inspirals

Daniel Baumann*, Gianfranco Bertone, John Stout, and Giovanni Maria Tomaselli
Phys. Rev. Lett. 128, 221102 (2022) [Featured in Physics & Editors' Suggestion]
DOI: https://doi.org/10.1103/PhysRevLett.128.221102

If new ultralight particles exist in nature, black holes would be surrounded by a cloud of such particles that behaves surprisingly similar to the cloud of electrons in an atom. When another heavy object spirals in and eventually merges with the black hole, the gravitational atom gets ionized and emits particles just like electrons are emitted when light is shone onto a metal. This can lead to characteristic signatures in the gravitational waves emitted by the binary which could be observed by future experiments.