Which gravitational waves actually carry spinning energy away from black holes?

Perturbing a Bardeen regular black hole (a singularity-free alternative to the standard Kerr/Schwarzschild solutions) and tracking the angular momentum carried away by gravitational waves reveals a sharp selection rule: only even-numbered wave modes (quadrupole, hexadecapole…) transport spin, while odd modes contribute nothing. The calculation uses the teleparallel formulation of general relativity to get a clean closed-form expression. This multipolar filter could leave a detectable imprint on gravitational-wave signals from regular black holes versus singular ones.