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arXiv · 2106.08836

Axion clouds may survive the perturbative tidal interaction over the early inspiral phase of black hole binaries

Takuya Takahashi·Takahiro Tanaka
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Abstract

Gravitational wave observation has the potential of probing ultralight bosonic fields such as axion. Axion forms a cloud around a rotating black hole (BH) by superradiant instability and should affect the gravitational waveform from binary BHs. On the other hand, considering the cloud associated with a BH in a binary system, tidal interaction depletes the cloud in some cases during the inspiral phase. We made the exhaustive study of cloud depletion numerically in a wide parameter range for equal mass binaries, assuming only the quadrupolar tidal perturbation is at work. We found that clouds can avoid disappearing due to the tidal effect only when $l=1$ mode is the fastest growing mode and when the binary orbit is counter-rotating in the non-relativistic parameter region.

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Takuya Takahashi, Takahiro Tanaka. 2021-08-25. Axion clouds may survive the perturbative tidal interaction over the early inspiral phase of black hole binaries. https://doi.org/10.1088/1475-7516%2F2021%2F10%2F031

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