On the Theoretical Framework of Magnetized Outflows from Stellar-Mass Black Holes and Related Observations

TL;DR

This paper develops a theoretical framework showing that the power of magnetized outflows from stellar-mass black holes depends nonlinearly on spin, challenging previous quadratic assumptions and aligning with some observational data.

Contribution

It introduces a nonlinear model for black hole jet power dependence on spin, accounting for magnetic fields, and clarifies discrepancies in observational correlations.

Findings

Black hole jet power scales nonlinearly with spin.

Previous quadratic models are inadequate when magnetic fields are considered.

Inner accretion disk power exceeds jet power and is significant.

Abstract

The spins of stellar-mass black holes (BHs) and the power outputs of their jets are measurable quantities. Unfortunately, the currently employed methods do not agree and the results are controversial. Two major issues concern the measurements of BH spin and beam (jet) power. The former issue can be resolved by future observations. But the latter issue can be resolved now, if we pay attention to what is expected from theoretical considerations. The question of whether a correlation has been found between the power outputs of few objects and the spins of their BHs is moot because BH beam power does not scale with the square of the spin of the BH. We show that the theoretical BH beam power is a strongly nonlinear function of spin that cannot be approximated by a quadratic relation, as is generally stated when the influence of the magnetic field is not accounted for in the \cite{bla77} model. The BH beam power of ballistic jets should scale a lot more steeply with BH spin irrespective of the magnetic field assumed to thread the horizon and the spin range considered. This behavior may already be visible in the analyses of radio observations by \cite{nar12} and \cite{rus13}. In agreement with previous studies, we also find that the power output that originates in the inner regions of the surrounding accretion disks is higher than that from the BHs and it cannot be ignored in investigations of continuous compact jets from these systems.