The missing asymptotic sector of rotating black-hole spectroscopy

The rotation of a Kerr black hole splits its low-frequency spectrum in two, so it was so far unclear why the known highly-damped resonances show no splitting. We find the missing, split sector, with spin s   quasinormal modes approaching the total reflection frequencies ω(n∈N)=−ΩΔJ−iκ(n−s)ω(n∈N)=−ΩΔJ−iκ(n−s), where Ω, κ and ΔJ are the horizon's angular velocity, surface gravity, and induced change in angular momentum. Surprisingly, the new sector is at least partly polar, and corresponds to reversible J transitions. Its fundamental branch converges quickly, possibly affecting gravitational wave signals. A simple interpretation of the Carter constant of motion is proposed.