2014

Distinguishing black-hole spin-orbit resonances by their gravitational-wave signatures

Gerosa, Davide, O'Shaughnessy, Richard, Kesden, Michael et al.

Understand

If binary black holes form following the successive core collapses of sufficiently massive binary stars, precessional dynamics may align their spins $\mathbf S_1$ and $\mathbf S_2$ and the orbital angular momentum $\mathbf L$ into a plane in which they jointly precess about the total angular momentum $\mathbf J$.

  • These spin orientations are known as spin-orbit resonances since $\mathbf S_1$, $\mathbf S_2$, and $\mathbf L$ all precess at the same frequency to maintain their planar configuration.
  • Two families of such spin-orbit resonances exist, alike in dignity but differentiated by whether the components of the two spins in the orbital plane are either aligned or antialigned.
  • The fraction of binary black holes in each family is determined by the stellar evolution of their progenitors, so if gravitational-wave detectors could measure this fraction they could provide important insights into astrophysical formation scenarios for binary black holes.

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