Geodesics and Symmetries of Doubly-Spinning Black Rings

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This paper studies various properties of the Pomeransky-Sen'kov doubly-spinning black ring spacetime.

• I discuss the structure of the ergoregion, and then go on to demonstrate the separability of the Hamilton-Jacobi equation for null, zero energy geodesics, which exist in the ergoregion.
• These geodesics are used to construct geometrically motivated coordinates that cover the black hole horizon.
• Finally, I relate this weak form of separability to the existence of a conformal Killing tensor in a particular 4-dimensional spacetime obtained by Kaluza-Klein reduction, and show that a related conformal Killing-Yano tensor only exists in the singly-spinning case.