The PP - Wave Limits of Orbifolded AdS 5 × S 5

Using the supergravity solution of N1 D3-branes probing AN2−1 singularities we study the pp-wave limit of AdS5×S/ZN2 . We show that there are two different pp-wave limits. One is the orbifold of the pp-wave limit of AdS5×S. In this case there is no symmetry enhancement. The other case is the same as the pp-wave limit of AdS5 × S and therefore we again see the maximal supersymmetry. We will also identify operators in the four dimensional N = 2 SU(N1) N2 gauge theory which correspond to stringy excitations in the orbifolded pp-wave geometry. The existence of the maximal pp-wave geometry indicates that there is a subsector of the corresponding N = 2 gauge theories which has enhanced N = 4 supersymmetry. We also study the pp-wave limits of AdS7,4 × S/ZN .