Extremal Charged Black Holes with a Twisted Extra Dimension

Understand

We construct odd-dimensional extremal charged black hole solutions with a twisted S^1 as an extra dimension on generalized Euclidean Taub-NUT spaces.

• There exists a null hypersurface where an expansion for an outgoing null geodesic congruence vanishes, then these spacetimes look like black holes.
• We show that the metrics admit C^0 extension across the horizon, but some components of Riemann curvature diverge there if the dimension is higher than five.
• The singularity is not much strong so that an observer along a free-fall geodesic can traverse the horizon.