Stability and Instability of Extreme Reissner-Nordstr\"om Black Hole   Spacetimes for Linear Scalar Perturbations II
  This paper contains the second part of a two-part series on the stability and instability of extreme Reissner-Nordstrom spacetimes for linear scalar perturbations. We continue our study of solutions to the linear wave equation on a suitable globally hyperbolic subset of such a spacetime, arising from regular initial data prescribed on a Cauchy hypersurface crossing the future event horizon. We here obtain definitive energy and pointwise decay, non-decay and blow-up results. Our estimates hold up to and including the horizon. A hierarchy of conservations laws on degenerate horizons is also derived. 
Stefanos Aretakis
gr-qc math-ph math.AP math.DG math.MP