Electromagnetic radiation from collisions at almost the speed of light: an extremely relativistic charged particle falling into a Schwarzschild black hole

TL;DR

This paper studies electromagnetic radiation emitted when a highly charged particle collides with a Schwarzschild black hole, revealing a flat spectrum and suppressed electromagnetic energy compared to gravitational energy at high energies.

Contribution

It provides a classical analysis of electromagnetic radiation during relativistic black hole collisions and compares electromagnetic and gravitational energy emissions at high energies.

Findings

Spectra is flat and well described by classical calculations.

Electromagnetic energy emission is suppressed relative to gravitational energy at high energies.

Results may apply to astrophysical collisions and high-energy experiments, with some extrapolation to higher dimensions.

Abstract

We investigate the electromagnetic radiation released during the high energy collision of a charged point particle with a four-dimensional Schwarzschild black hole. We show that the spectra is flat, and well described by a classical calculation. We also compare the total electromagnetic and gravitational energies emitted, and find that the former is supressed in relation to the latter for very high energies. These results could apply to the astrophysical world in the case charged stars and small charged black holes are out there colliding into large black holes, and to a very high energy collision experiment in a four-dimensional world. In this latter scenario the calculation is to be used for the moments just after the black hole formation, when the collision of charged debris with the newly formed black hole is certainly expected. Since the calculation is four-dimensional, it does not directly apply to Tev-scale gravity black holes, as these inhabit a world of six to eleven dimensions, although our results should qualitatively hold when extrapolated with some care to higher dimensions.