Collisional Penrose Process near the Horizon of Extreme Kerr Black Holes
Journal article, 2012

Collisions of particles in black hole ergospheres may result in an arbitrarily large center-of-mass energy. This led recently to the suggestion [M. Banados, J. Silk, and S. M. West, Phys. Rev. Lett. 103, 111102 (2009)] that black holes can act as ultimate particle accelerators. If the energy of an outgoing particle is larger than the total energy of the infalling particles, the energy excess must come from the rotational energy of the black hole and hence, a Penrose process is involved. However, while the center-of-mass energy diverges, the position of the collision makes it impossible for energetic particles to escape to infinity. Following an earlier work on collisional Penrose processes [T. Piran and J. Shaham, Phys. Rev. D 16, 1615 (1977)], we show that even under the most favorable idealized conditions the maximal energy of an escaping particle is only a modest factor above the total initial energy of the colliding particles. This implies that one should not expect collisions around a black hole to act as spectacular cosmic accelerators.

extraction

energy

Author

M. Bejger

T. Piran

Marek A Abramowicz

University of Gothenburg

Frida Håkansson

Chalmers, Earth and Space Sciences, Nonlinear electrodynamics

Physical Review Letters

0031-9007 (ISSN) 1079-7114 (eISSN)

Vol. 109 12 artikel nr 121101- 121101

Subject Categories

Physical Sciences

DOI

10.1103/PhysRevLett.109.121101

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