On Static Charged Black Holes in Type IIA on a Nearly-Kahler Coset

We study static, spherically symmetric black hole solutions in four-dimensional N=2 gauged supergravity with one vector multiplet and one hyper-tensor multiplet. This is derived from massive type IIA theory compactified on the nearly-Kahler coset space G2/SU(3). It is well-known that the Romans' mass parameter yields the Stuckelberg-type deformation of the gauge field strengths in the four-dimensional system. This deformation requires that all the (covariant) derivatives of the scalar fields must vanish and the two-form field is closed. It turns out that charged solutions are forbidden. This implies that only AdS vacua or Schwarzschild-AdS black holes are allowed as the static, spherically symmetric solutions.Comment: 13 page

Defect (p,q) Five-branes

We study a local description of composite five-branes of codimension two. The formulation is constructed by virtue of $SL(2,{\mathbb Z}) \times SL(2,{\mathbb Z)}$ monodromy associated with two-torus. Applying conjugate monodromy transformations to the complex structures of the two-torus, we obtain a field configuration of a defect $(p,q)$ five-brane. This is a composite state of $p$ defect NS5-branes and $q$ exotic $5^2_2$-branes. We also obtain a new example of hyper-K\"{a}hler geometry. This is an ALG space, a generalization of an ALF space which asymptotically has a tri-holomorphic two-torus action. This geometry appears in the conjugate configuration of a single defect KK5-brane.Comment: 22 pages, version published in Nuclear Physics