The missing asymptotic sector of rotating black-hole spectroscopy

TL;DR

This paper uncovers a previously unknown sector of rotating black-hole quasinormal modes in the highly-damped regime, revealing new spectral features related to black hole rotation and field interactions.

Contribution

It identifies and characterizes the second, oblate sector of black-hole spectra, extending understanding of black-hole quasinormal modes in the highly-damped regime.

Findings

Discovery of the second oblate sector of quasinormal modes.

Modes approach the total reflection frequencies (n>>1) ~ mb7 - 2 iT(n-s).

Physical implications for black-hole spectroscopy discussed.

Abstract

The rotation of a black hole splits its spectrum in two, yet only one sector is known in the highly-damped regime. We find the second, at least partly oblate sector, with quasinormal modes approaching the total reflection frequencies \omega(n>>1) ~ m\Omega - 2\pi iT(n-s), where \Omega and T are the horizon angular velocity and temperature, s is the field spin, and m is an azimuthal eigenvalue. Some physical implications are discussed.