A Penrose limit for type IIB AdS6 solutions

In this paper a Penrose limit is constructed for type IIB $AdS_6\times S^2\times \Sigma$ supergravity solutions. These solutions are dual to five dimensional SCFTs related (p,q) brane webs, which can often be described in terms of long quiver gauge theories. The null geodesic from the localized at unique point on two Riemann surface $\Sigma$, where $AdS_6$ and $S^2$ metric factors extremal. resulting pp-wave spacetime takes universal form. world sheet action Green-Schwarz string quadratic light cone spectrum excitations obtained.