Comment on `An extreme critical space-time: echoing and black-hole perturbations'

TL;DR

This paper demonstrates that certain black hole perturbations in a specific solution are actually gauge artifacts caused by coordinate transformations, clarifying the nature of these perturbations.

Contribution

It reveals that the perturbations previously thought to be physical are actually gauge artifacts, providing a clearer understanding of the perturbation structure in the Hayward black hole solution.

Findings

Black hole perturbations are gauge artifacts.

Perturbations result from linearized coordinate transformations.

Clarifies the physical significance of perturbations in this context.

Abstract

We show that the black hole perturbations of the Hayward static solution to the massless Einstein-Klein-Gordon equations are actually gauge artifacts resulting from the linearization of a coordinate transformation.