A Charged Rotating Black Ring

TL;DR

This paper constructs a supergravity solution for a charged rotating black ring in five dimensions, revealing how electric charge influences stability and extremal limits, extending previous neutral black ring solutions.

Contribution

It provides the first explicit supergravity solution for a charged rotating black ring, including analysis of bounds on angular momentum and charge effects.

Findings

Charged black ring supports against gravity with electric charge.

The lower bound on J^2/M^3 is determined and saturated by a maximum entropy solution.

An extremal limit exists where the horizon coincides with the singularity.

Abstract

We construct a supergravity solution describing a charged rotating black ring with S^2xS^1 horizon in a five dimensional asymptotically flat spacetime. In the neutral limit the solution is the rotating black ring recently found by Emparan and Reall. We determine the exact value of the lower bound on J^2/M^3, where J is the angular momentum and M the mass; the black ring saturating this bound has maximum entropy for the given mass. The charged black ring is characterized by mass M, angular momentum J, and electric charge Q, and it also carries local fundamental string charge. The electric charge distributed uniformly along the ring helps support the ring against its gravitational self-attraction, so that J^2/M^3 can be made arbitrarily small while Q/M remains finite. The charged black ring has an extremal limit in which the horizon coincides with the singularity.