Electromagnetic radiation generated by a charged particle plunging into a Schwarzschild black hole: Multipolar waveforms and ringdowns

TL;DR

This paper analyzes electromagnetic radiation from a charged particle plunging into a Schwarzschild black hole, focusing on multipolar waveforms and ringdowns, highlighting the significance of higher harmonics in waveform distortion.

Contribution

It provides gauge-invariant multipolar waveforms for electromagnetic perturbations during a plunge, including regularized and unregularized spectra for arbitrary observation angles.

Findings

Excellent agreement between regularized and unregularized waveforms.

Higher harmonics significantly affect waveform distortion.

Results applicable for arbitrary observation directions.

Abstract

Electromagnetic radiation emitted by a charged particle plunging from slightly below the innermost stable circular orbit into a Schwarzschild black hole is examined. Both even- and odd-parity electromagnetic perturbations are considered. They are described by using gauge invariant master functions and the regularized multipolar waveforms as well as their unregularized counterparts constructed from the quasinormal-mode spectrum are obtained for arbitrary directions of observation and, in particular, outside the orbital plane of the plunging particle. They are in excellent agreement and the results especially emphasize the impact of higher harmonics on the distortion of the waveforms.