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arXiv · 1811.05979

Wide nutation: binary black-hole spins repeatedly oscillating from full alignment to full anti-alignment

Davide Gerosa·Alicia Lima·Emanuele Berti·Ulrich Sperhake·Michael Kesden·Richard O'Shaughnessy
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Abstract

Within the framework of 2PN black-hole binary spin precession, we explore configurations where one of the two spins oscillates from being completely aligned with the orbital angular momentum to being completely anti-aligned with it during a single precession cycle. This "wide nutation" is the extreme limit of the generic phenomenon of spin nutation in black-hole binaries. Crucially, wide nutation happens on the short precession time scale and it is not a secular effect due to gravitational-wave radiation reaction. The spins of these binaries, therefore, flip repeatedly as one of these special configurations is entered. Binaries with total mass $M$, mass ratio $q$, and dimensionless spin $χ_1$ ($χ_2$) of the more (less) massive black hole are allowed to undergo wide nutation at binary separations $r \leq r_{\rm wide} \equiv [(q χ_2 - χ_1)/(1-q)]^2 M$. Sources that are more likely to nutate widely have similar masses and effective spins close to zero.

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Davide Gerosa, Alicia Lima, Emanuele Berti, Ulrich Sperhake, Michael Kesden, Richard O'Shaughnessy. 2019-04-15. Wide nutation: binary black-hole spins repeatedly oscillating from full alignment to full anti-alignment. https://doi.org/10.1088/1361-6382%2Fab14ae

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