Is radio jet power linearly proportional to the product of central black hole mass and Eddington ratio in AGN?

TL;DR

This paper proposes a model linking radio jet power to black hole mass and Eddington ratio in AGN, finding that the relationship is complex and varies with accretion rate and AGN type, suggesting different jet powering mechanisms.

Contribution

The study introduces a model describing the non-linear relation between jet power and the product of black hole mass and Eddington ratio, supported by literature data.

Findings

Radio jet power correlates positively but non-linearly with the product of BH mass and Eddington ratio.

Low accretion AGN show a negative correlation between radio loudness and the product of BH mass and Eddington ratio.

High-redshift quasars likely have jet power dominated by accretion disc rather than black hole spin.

Abstract

A model for the relation between radio jet power and the product of central black hole (BH) mass and Eddington ratio of AGN is proposed, and the model is examined with data from the literature. We find that radio jet power positively correlates but not linearly with the product of BH mass ($m$ in solar mass) and Eddington ratio ($\lambda$), and the power law indices ($\mu$) are significantly less than unity for relatively low accretion ($\lambda<0.1$) AGN, $P_{j}\propto (\lambda m)^{\mu}$, in the radio galaxies and the Seyfert galaxies. This leads to a negative correlation between radio loudness and $\lambda m$ for the low luminosity AGN, i.e. $R\propto (\lambda m)^{\rho}$ with $\rho=(7/6)\mu-1<0$, which may be attributed to a contribution of BH spin to total jet power assuming that the spin induced jet is gradually suppressed as the accretion rate increases. Whereas, for the high-z quasars which often show the slope $\mu\geq1$, a positive correlation between the radio loudness and disc luminosity is predicted. We discuss that the jet powers of the high-z FRII quasars are likely dominated by the accretion disc rather than by the BH spin.