Note on (D6,D8) Bound State, Massive Duality and Non-commutativity

Abstract

In this paper we study half-supersymmetric (D6,D8) bound state brane configuration of massive type IIA supergravity. We show that this bound state can also be generated by using massive T-duality rules of type-II supergravities in D=9, starting from D7-branes. We write down corresponding Killing spinors and find that these backgrounds indeed preserve 16 supersymmetries like any other D$p$-brane bound state with $B$-field. We also make a point on the massive nature of the $B$-field in this background. The Seiberg-Witten limits to obtain 9-dimensional NCYMs are also discussed, but the full understanding of such gauge theories remains unanswered.