Quasi-normal modes of Schwarzschild-de Sitter black holes

TL;DR

This paper calculates the quasi-normal modes of Schwarzschild-de Sitter black holes for various fields using advanced approximation methods, generalizing known formulas and showing agreement in certain limits.

Contribution

It introduces a generalized asymptotic formula for QNM frequencies of Schwarzschild-de Sitter black holes applicable to different spins.

Findings

Good agreement between methods in the near-extreme limit

Fields of different spin decay at the same rate in this limit

Generalization of the large $l$ asymptotic formula

Abstract

The low-laying frequencies of characteristic quasi-normal modes (QNM) of Schwarzschild-de Sitter (SdS) black holes have been calculated for fields of different spin using the 6th-order WKB approximation and the approximation by the P\"{o}shl-Teller potential. The well-known asymptotic formula for large $l$ is generalized here on a case of the Schwarzchild-de Sitter black hole. In the limit of the near extreme $\Lambda$ term the results given by both methods are in a very good agreement, and in this limit fields of different spin decay with the same rate.