Superstring theory on AdS3 x G/H and boundary N=3 superconformal symmetry

Superstrings propagating on backgrounds of the form AdS(3) x G/H are studied using the coset CFT approach. We focus on seven dimensional cosets which have a semiclassical limit, and which give rise to N = 3 superconformal symmetry in the dual CFT. This is realized for the two cases AdS(3) x SU(3)/U(1) and AdS(3) x SO(5)/SO(3), for which we present an explicit construction. We also provide sufficient conditions on a CFT background to enable a similar construction, and comment on the geometrical interpretation of our results.