Perturbations and absorption cross section of infinite-radius black rings

We study scalar field perturbations on the background of nonsupersymmetric black rings and of supersymmetric black rings. In the infinite-radius limit of these geometries, we are able to separate the wave equation, and to study wave phenomena in its vicinities. In this limit, we show that (i) the nonsupersymmetric case is stable against scalar field perturbations (ii) the low energy absorption cross section for scalar fields is equal to the area of the event horizon in the supersymmetric case, and proportional to it in the nonsupersymmetric situation.