  Utilizing recent mathematical advances in proving stability of Minkowski
spacetime with minimal decay rates and nonlinear stability of Kerr black holes
with small angular momentum, we investigate the detailed asymptotic behaviors
of gravitational waves generated in these spacetimes. Here we report and
propose a new angular momentum memory effect along future null infinity. This
accompanies Christodoulou's nonlinear displacement memory effect and the spin
memory effect. The connections and differences to these effects are also
addressed.
