Analysis of gravitational radiation generated by type D black holes with positive cosmological constant

TL;DR

This paper investigates gravitational radiation from type D black holes with a positive cosmological constant, confirming that only accelerating black holes emit measurable gravitational waves at infinity, using a new metric form for analysis.

Contribution

The authors develop a new metric form for type D black holes with cosmological constant and electromagnetic fields, and apply a radiation criterion to determine which black holes emit gravitational waves.

Findings

Only accelerating black holes generate measurable gravitational radiation.

The new metric form facilitates analysis of asymptotic spacetime structure.

The criterion for gravitational radiation is validated for these solutions.

Abstract

The criterion for existence of gravitational radiation at conformal infinity in the presence of a positive cosmological constant is applied to a general family of exact solutions representing generic (pairs of) black holes of algebraic type D. Our analysis shows that only accelerating black holes generate gravitational radiation measurable at infinity. This very satisfactory result confirms the goodness of the criterion. To that end, a new metric form of the family of exact type D black holes is constructed -- including any cosmological constant and a (double-aligned) non-null electromagnetic field -- whose expression is suitable for investigation of the asymptotic structure of this large family of spacetimes. The family depends on seven physical parameters, namely $m$, $a$, $l$, $\alpha$, $e$, $g$, and $\Lambda$ that characterize mass, specific angular momentum parameter, NUT parameter, acceleration, electric and magnetic charges, and the cosmological constant, respectively.