Structure of Kerr black hole spacetimes in Weyl conformal gravity

TL;DR

This paper studies the structure of rotating black hole solutions in Weyl conformal gravity, comparing their causal and ergoregion features to those in general relativity, and analyzing extremal limits and thermodynamic properties.

Contribution

It provides a detailed analysis of Kerr-like solutions in Weyl conformal gravity, including their causal structure, extremal limits, and thermodynamic characteristics, which are novel compared to prior work in GR.

Findings

Causal and ergoregion structures are characterized for Weyl gravity black holes.

Extremal limits for horizons and ergosurfaces are derived and analyzed.

Horizon surface gravities and Hawking temperatures vanish at extremal limits.

Abstract

We analyze the stationary, uncharged, rotating, vacuum solution to Weyl conformal gravity. We elucidate the causal and ergoregion structure of the spacetimes found in the parameter space of the metric for positive mass. These are then compared to the analogous Kerr, Kerr-de Sitter, and Kerr-Anti-de Sitter solutions to general relativity. Additionally, we investigate and derive the extremal limits for both the horizons and ergosurfaces of the spacetimes. The horizon surface gravities and Hawking temperatures at the extremal horizon limits are then calculated to show that they vanish.