Photon emissions from near-horizon extremal and near-extremal Kerr equatorial emitters

Abstract

We consider isotropic and monochromatic photon emissions from equatorial emitters moving along future-directed timelike geodesics in the near-horizon extremal Kerr (NHEK) and near-horizon near-extremal Kerr (near-NHEK) regions, to asymptotic infinity. We obtain numerical results for the photon escaping probability (PEP) and derive analytical expressions for the maximum observable blueshift (MOB) of the escaping photons, both depending on the emission radius and the emitter's proper motion. In particular, we find that for all anti-plunging or deflecting emitters that can eventually reach to asymptotic infinity, the PEP is greater than $50\%$ while for all plunging emitters the PEP is less than $55\%$, and for the bounded emitters in the (near-)NHEK region, the PEP is always less than $59\%$. In addition, for the emitters on unstable circular orbits in the near-NHEK region, the PEP decreases from $55\%$ to $50\%$ as the orbital radius decreases from the one of the innermost stable circular orbit to the one of the horizon. Furthermore, we show how the orientation of the emitter's motion along the radial or azimuthal direction affects the PEP and the MOB of the emitted photons.

Slight change in title, matched the published version in PRD

References in corpus (26)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon
• Black Hole Shadows, Photon Rings, and Lensing Rings
• Stationary black holes and light rings
• The Shape of the Black Hole Photon Ring: A Precise Test of Strong-Field General Relativity
• Influence of Quantum Correction on the Black Hole Shadows, Photon Rings and Lensing Rings
• Universal Polarimetric Signatures of the Black Hole Photon Ring
• Universal Properties of Light Rings for Stationary Axisymmetric Spacetimes
• Revised upper limit to energy extraction from a Kerr black hole
• Ultra-high-energy debris from the collisional Penrose process
• Influence of a plasma on the observational signature of a high-spin Kerr black hole
• Gravity Waves from Extreme-Mass-Ratio Plunges into Kerr Black Holes
• Charged spinning black holes as accelerators of spinning particles
• Observational signature of a near-extremal Kerr-Sen black hole in the heterotic string theory
• The light ring and the appearance of matter accreted by black holes
• Maximum Observable Blueshift from Circular Equatorial Kerr Orbiters
• Escape probability of a photon emitted near the black hole horizon
• Photon Emission from Circular Equatorial Kerr Orbiters
• Near-horizon geodesics of high-spin black holes
• Observability of the innermost stable circular orbit in a near-extremal Kerr black hole
• Escape probability of particle from Kerr-Sen black hole
• Emissions of photons near the horizons of Kerr-Sen black holes
• Photon emission from inside the innermost stable circular orbit
• Force-free magnetosphere attractors for near-horizon extreme and near-extreme limits of Kerr black hole
• Observability of Zero-angular-momentum Sources Near Kerr Black Holes
• Electro-Magnetic Energy Extraction from Rotating Black Holes in AdS

Cited by in corpus (2)

• Geodesic structure, shadow and optical appearance of black hole immersed in Chaplygin-like dark fluid
• Photon escape in the extremal Kerr black hole spacetime