Spinformation: do gravitational-wave events carry information beyond effective spins?

The name says it all: spinformation! Measuring spins in gravitational-wave events is a tricky business. There are two spins, so 6 numbers (both are vectors), but we actually mostly measure some combinations of these and the black-hole masses. These are the effective spins people talk about, and it’s actually unclear whether we measure only the effective spins or mostly the effective spins. That’s what we try to investigate in this paper, going beyond effective spins and chasing the spinformation in our GW catalog.

C. Plunkett, J. Heinzel, N. E. Wolfe, D. Gerosa, S. Vitale.
arXiv:2609.31879 [astro-ph.HE].