Instantons and wormholes in AdS(3) x S-3 x CY2

We study supergravity instantons sourced by axion (and saxion) fields in the Euclidean AdS(3) x S-3 x CY2 vacua of IIB supergravity. Such instantons are described by geodesic curves on the moduli space; the timelike geodesics can describe Euclidean wormholes, the lightlike geodesics describe (generalizations of) D instantons, and spacelike geodesics are subextremal versions thereof. We perform a concrete classification of such geodesics and find that, despite earlier claims, the wormholes fail to be regular. A subclass of the lightlike geodesics is supersymmetric and, up to dualities, lifts to Euclidean strings wrapping 2-cycles in the CY2. The dual of these instantons is expected to be worldsheet instantons of the D1-D5 conformal field theory.