2015/01/29 by M. Colleoni, Marta Colleoni, Leor Barack
Mathematics · Physics and Astronomy · #Angular momentum #Astrophysical Phenomena and Observations #Black Holes and Theoretical Physics #Black hole (networking) #Classical mechanics #Conservative force #Cosmic censorship hypothesis #Dissipative system #General relativity #Geodesic #Geometry #Gravitation #Mathematical analysis #Mathematics #Parameter space #Physics #Pulsars and Gravitational Waves Research #Quantum mechanics #Rotating black hole #Spacetime #gr-qc
paper · pdf · doi:10.1103/physrevd.91.104024
25 pages, 4 figures
arxiv created 2015/01/29 · openalex publication_date 2015/05/20 · arxiv updated 2015/06/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study the scenario in which a massive particle is thrown into a rapidly rotating Kerr black hole in an attempt to spin it up beyond its extremal limit, challenging weak cosmic censorship. We work in black-hole perturbation theory, and focus on nonspinning, uncharged particles sent in on equatorial orbits. We first identify the complete parameter-space region in which overspinning occurs when backreaction effects from the particle's self-gravity are ignored. We find, in particular, that overspinning can be achieved only with particles sent in from infinity. Gravitational self-force effects may prevent overspinning by radiating away a sufficient amount of the particle's angular momentum (``dissipative effect''), and/or by increasing the effective centrifugal repulsion, so that particles with suitable parameters never get captured (``conservative effect''). We analyze the full effect of the self-force, thereby completing previous studies by Jacobson and Sotiriou (who neglected the self-force) and by Barausse, Cardoso and Khanna (who considered the dissipative effect on a subset of orbits). Our main result is an inequality, involving certain self-force quantities, which describes a necessary and sufficient condition for the overspinning scenario to be overruled. This ``censorship'' condition is formulated on a certain one-parameter family of geodesics in the limit of an extremal Kerr geometry. We find that the censorship condition is insensitive to the dissipative effect (within the first-order self-force approximation used here), except for a subset of perfectly fine-tuned orbits, for which a separate censorship condition is derived. We do not obtain here the self-force input needed to evaluate either of our two conditions, but discuss the prospects for producing the necessary data using state-of-the-art numerical codes.