Bubbling geometries for AdS_2 x S^2

We construct BPS geometries describing normalizable excitations of AdS_2 x S^2. All regular horizon-free solutions are parameterized by two harmonic functions in R^3 with sources along closed curves. This local structure is reminiscent of the "bubbling solutions" for the other AdS cases, however, due to peculiar asymptotic properties of AdS_2, one copy of R^3 does not cover the entire space, and we discuss the procedure for analytic continuation, which leads to a nontrivial topological structure of the new geometries. We also study supersymmetric brane probes on the new geometries, which represent the AdS_2 x S^2 counterparts of the giant gravitons.