Photon Emission Near Extreme Kerr Black Holes

TL;DR

This paper analytically derives null geodesics near extremally spinning Kerr black holes using near-horizon conformal symmetry, aiding the interpretation of electromagnetic emissions from black hole vicinities.

Contribution

It introduces an analytical method for finding near-superradiant geodesics around extremal Kerr black holes, leveraging near-horizon conformal symmetry.

Findings

Analytical expressions for near-horizon geodesics in extremal Kerr black holes.

Enhanced understanding of electromagnetic emissions near black holes.

Potential applications in black hole imaging and astrophysics.

Abstract

Ongoing astronomical efforts extract physical properties of black holes from electromagnetic emissions in their near-vicinity. This requires finding the null geodesics which extend from the near-horizon region out to a distant observatory. In general these can only be found numerically. In this paper, for the interesting special case of extremally spinning Kerr black holes, we use an emergent near-horizon conformal symmetry to find near-superradiant geodesics analytically.