Optimal decay for solutions of the Teukolsky equation on the Kerr metric for the full subextremal range |a| < M

We derive the large time asymptotics of initially regular and localized solutions of the Teukolsky equation on the exterior of a subextremal Kerr black hole for any half integer spin. More precisely, we obtain the leading order term (predicted by Price’s law) in the large time regime assuming that the initial data have compact support and have enough (but finite) Sobolev regularity. For initial data with less spatial decay (typically decaying like r^{–1–$\alpha$} with $\alpha$ $\in$ (0, 1)), we prove that the solution has a pointwise decay of order t^{–1–$\alpha$–s–|s|+} on spatially compact regions. In the proof, we adopt the spectral point of view and make use of recent advances in microlocal analysis and non elliptic Fredholm theory which provide a robust framework to study linear operators on black hole type spacetimes.