Dynamical D4-D8 branes in supergravity

We present a class of dynamical solutions for an intersecting D4-D8 brane system in ten-dimensional type IIA supergravity. The dynamical solutions reduces to a static warped AdS6 × S geometry in a certain spacetime region. We also consider lower-dimensional effective theories for the warped compactification of general p-brane system. It is found that an effective p + 1-dimensional description is not possible in general due to the entanglement of the transverse coordinates and the p+1-dimensional coordinates in the metric components. Then we discuss cosmological solutions. We find a solution that behaves like a Kasner-type cosmological solution at τ → ∞, while it reduces to a warped static solution at τ → 0, where τ is the cosmic time.