Hairy Black Holes: Non-existence of Short Hairs and Bound on Light Ring Size

Abstract

Several hairy black hole solutions are known to violate the original version of the celebrated no-hair conjecture. This prompted the development of a new theorem that establishes a universal lower bound on the extension of hairs outside any $4$-dimensional black hole solutions of general relativity. Our work presents a novel generalization of this ``no-short hair'' theorem, which notably does not use gravitational field equations and is valid for arbitrary spacetime dimensions ($D\ge 4$). Consequently, irrespective of the underlying theory of gravity, the ``hairosphere'' must extend to the innermost light ring of the black hole spacetime. Various possible observational implications of this intriguing theorem are discussed, and other useful consequences are explored.

7 pages, no figure

References in corpus (7)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• Constraints on black-hole charges with the 2017 EHT observations of M87*
• Observable Properties of Orbits in Exact Bumpy Spacetimes
• Upper bound on the radii of black-hole photonspheres
• Rotating black holes can have short bristles
• Self-gravitating field configurations: The role of the energy-momentum trace
• Bound on photon circular orbits in general relativity and beyond

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