Black Hole Spin Energy Contribution to Black Hole Mass and the Spin Energy Reservoir

TL;DR

This paper quantifies the contribution of black hole spin energy to the total black hole mass across various sources, showing it can account for up to about 30%, with implications for black hole evolution and galaxy relationships.

Contribution

It provides the first comprehensive analysis of spin energy contribution to black hole mass across multiple source types, including LINERs, radio sources, AGN, and X-ray binaries.

Findings

Spin energy contributes 10-30% of black hole mass.

Typical extractable mass fraction is about 20%.

Results align with theoretical expectations and simulations.

Abstract

The mass of a black hole is the sum of the irreducible mass and the mass associated with the rotational or spin energy of the black hole. The contribution of spin energy (divided by $c^2$) to the total black hole mass is studied here for four samples of sources including 576 LINERs, 100 classical double radio sources, 80 relatively local AGN, and 102 measurements of four stellar mass X-ray binary systems. The spin mass-energy of a black hole may be extracted causing the mass of the black hole to decrease. The ratio of spin mass-energy to black hole mass ranges from about ten to thirty percent for the sources studied here, where the maximum possible value of this quantity is close to thirty percent. Typical fractions of the black hole mass available for extraction for the samples studied are about $0.2 \pm 0.1$. The spin energy of black holes represents a major reservoir that when tapped may impact the immediate and extended black hole environment, decrease the black hole mass, and perhaps modify relationships between black hole mass and galaxy properties. These results are consistent with expectations based on other observations and numerical simulations.