Escape probability of a photon emitted near the black hole horizon

Abstract

We investigate the escape of photons from the vicinity of the horizon to infinity in the Kerr-Newmann black hole spacetime. We assume that a light source is at rest in a locally nonrotating frame and photons are emitted isotropically. Then, we evaluate the escape probability of the emitted photons. The main result of this paper is the following. If the black hole is extremal with the nondimensional spin parameter $a_{\ast }>1/2$, however close to the horizon the light source would be, the escape probability remains nonzero. The near-horizon limit value of the escape probability is a monotonically increasing function of $a_{\ast }$ and takes a maximum $\sim$29.1\% at $a_{\ast }=1$, i.e., for the extremal Kerr case. On the other hand, if the black hole is extremal with $0\le a_{\ast }\le 1/2$ or if the black hole is subextremal, the near-horizon limit value is zero.

14 pages, 8 figures

References in corpus (6)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• Revised upper limit to energy extraction from a Kerr black hole
• Black holes as particle accelerators: a brief review
• Ultra-high-energy debris from the collisional Penrose process
• Completing characterization of photon orbits in Kerr and Kerr-Newman metrics
• Constraint on the black-hole spin of M87 from the accretion-jet model

Cited by in corpus (11)

• Photon regions and umbilic conditions in stationary axisymmetric spacetimes
• Observability of the innermost stable circular orbit in a near-extremal Kerr black hole
• Electromagnetic tests of horizonless rotating black hole mimickers
• Complete classification of photon escape in the Kerr black hole spacetime
• Emissions of photons near the horizons of Kerr-Sen black holes
• Null geodesics in extremal Kerr-Newman black holes
• Photon emission from inside the innermost stable circular orbit
• Photon emissions from near-horizon extremal and near-extremal Kerr equatorial emitters
• Observability of Zero-angular-momentum Sources Near Kerr Black Holes
• Photon escape in the extremal Kerr black hole spacetime
• Signatures of particle collisions near extreme black holes