The pp-wave limits of orbifolded AdS5×S5

Using the supergravity solution of N1 D3-branes probing AN2−1 singularities we study the pp-wave limit of AdS5×S5/ZN2. We show that there are two different pp-wave limits. One is the orbifold of the pp-wave limit of AdS5×S5. In this case there is no symmetry enhancement. The other case is the same as the pp-wave limit of AdS5×S5 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×S4,7/ZN.