Ruling Out Compact Jets as the Dominant Source of Radio Emission in Radio-quiet, High Eddington-ratio Active Galactic Nuclei

TL;DR

This study investigates whether jets are the main source of radio emission in radio-quiet, high Eddington-ratio AGNs, finding evidence against jet dominance and suggesting corona or outflow origins instead.

Contribution

It provides the first comprehensive analysis across a wide black hole mass range, challenging jet-based models for radio emission in high Eddington-ratio AGNs.

Findings

Radio/X-ray ratios are inconsistent with jet-dominated models.

Results support corona-dominated or outflow-related radio emission.

Findings apply across a broad black hole mass spectrum.

Abstract

The origin of core radio emission in radio-quiet active galactic nuclei (AGNs) is still actively debated. General relativistic magnetohydrodynamics simulations often predict the launching of moderately large-scale jets from super-Eddington accretion flows, but this prediction seems at odds with observations indicating most high/super-Eddington AGNs appear radio quiet. Here, we use the ratio of radio to X-ray luminosities as a multiwavelength diagnostic to probe the origin of radio emission in a sample of 69 radio-quiet, high/super-Eddington AGNs with black-hole masses $M_{\rm BH} \sim 10^{5}-10^{9}~M_\odot$. With this wide dynamic range in $M_{\rm BH}$, we adapt existing formalisms for how jetted radio emission and accretion-powered X-ray emission scale with black hole mass into the super-Eddington regime. We find that the radio/X-ray luminosity ratios observed across this $M_{\rm BH}$ range are inconsistent with a jet-dominated model for radio emission. We discuss how our results may instead be consistent with a corona-dominated radio emission origin with a contribution from outflows at higher accretion rates.