[On the jet contribution to the AGN cosmic energy budget

TL;DR

This paper assesses the energy contribution of jets from black holes compared to accretion disc emissions over cosmic time, finding jets contribute less than 10% to the AGN energy budget.

Contribution

It provides a novel comparison of the mechanical luminosity function of radio jets with the bolometric AGN luminosity across cosmic history.

Findings

Jets contribute less than 10% of the AGN energy budget at all epochs.

The mechanical luminosity function was derived from radio observations and compared to X-ray, optical, and infrared data.

Uncertainty remains due to the relation between radio luminosity and mechanical power.

Abstract

Black holes release energy via the production of photons in their accretion discs but also via the acceleration of jets. We investigate the relative importance of these two paths over cosmic time by determining the mechanical luminosity function (LF) of radio sources and by comparing it to a previous determination of the bolometric LF of active galactic nuclei (AGN) from X-ray, optical and infrared observations. The mechanical LF of radio sources is computed in two steps: the determination of the mechanical luminosity as a function of the radio luminosity and its convolution with the radio LF of radio sources. Even with the large uncertainty deriving from the former, we can conclude that the contribution of jets is unlikely to be much larger than 10% of the AGN energy budget at any cosmic epoch.