Near horizon geometry of strings ending on intersecting D8/D4-branes

Abstract

We consider solutions of massive IIA supergravity corresponding to the half-BPS intersection of D8/D4-branes with fundamental strings. The 1 + 1-dimensional intersection preserves the symmetry D(2, 1; γ; 1) × SO(4). We give a reduction and partial integration of the BPS equations for this symmetry group. We then specialize to the cases of enhanced supersymmetry corresponding to γ = −1/2, −2 or γ = 1. In the first case, we show that the only solution with enhanced symmetry is given by the AdS 6 geometry describing the near horizon geometry of D8/D4-branes in the presence of an O8-plane. In the second case, we identify novel solutions corresponding to fundamental strings ending on D8-branes and a second set of novel solutions corresponding to fundamental strings ending on an O8-plane. In both cases, the fundamental string geometry contains an asymptotically flat region where the string coupling goes to zero. We also show that there are no solutions corresponding to 1+0-dimensional CFTs, which one may have hoped to construct by suspending fundamental strings between D8-branes.