PP - waves in AdS Gauged Supergravities and Supernumerary

Purely gravitational pp-waves in AdS backgrounds are described by the generalised Kaigorodov metrics, and they preserve 1 4 of the maximum supersymmetry allowed by the AdS spacetimes. We construct pp-waves in gauged AdS supergravities supported by a field strength. We find that the solutions in D = 4 and D = 5 can then preserve 1 2 of the supersymmetry. Like those in ungauged supergravities, the supernumerary supersymme-try imposes additional constraints on the harmonic function associated with the pp-waves. These new backgrounds provide interesting novel features of the supersymmetry enhancement for the dual conformal field theory in the infinite-momentum frame.