  Gravitational waves contain tail effects that are due to the backscattering
of linear waves in the curved space-time geometry around the source. The
knowledge as well as the accuracy of the two-body inspiraling post-Newtonian
(PN) dynamics and of the gravitational-wave signal has been recently improved,
notably by computing the spin-orbit (SO) terms induced by tail effects in the
gravitational-wave energy flux at the 3PN order. Here we sketch this
derivation, which yields the phasing formula including SO tail effects through
the same 3PN order. Those results can be employed to improve the accuracy of
analytical templates aimed at describing the whole process of inspiral, merger,
and ringdown.
