A Distinctive Disk-Jet Coupling in the Seyfert-1 AGN NGC 4051

TL;DR

This study presents simultaneous X-ray and radio observations of NGC 4051, revealing an inverse disk-jet coupling that differs from the typical positive correlation, suggesting a distinct accretion mode at high Eddington ratios.

Contribution

It provides the first simultaneous measurement of radio and X-ray luminosities in NGC 4051, demonstrating a unique inverse correlation and proposing a new accretion-ejection mode in high Eddington systems.

Findings

Inverse correlation between radio and X-ray luminosities in NGC 4051.

Deviation from the fundamental plane of black hole accretion.

Inverse correlation also observed in three other high Eddington ratio systems.

Abstract

We report on the results of a simultaneous monitoring campaign employing eight Chandra X-ray (0.5-10 keV) and six VLA/EVLA (8.4 GHz) radio observations of NGC 4051 over seven months. Evidence for compact jets is observed in the 8.4 GHz radio band; This builds on mounting evidence that jet production may be prevalent even in radio-quiet Seyferts. Assuming comparatively negligible local diffuse emission in the nucleus, the results also demonstrate an inverse correlation of L_radio proportional to L_X-ray ^(-0.72+/-0.04) . Current research linking the mass of supermassive black holes and stellar-mass black holes in the "low/hard" state to X-ray luminosities and radio luminosities suggest a "fundamental plane of accretion onto black holes" that has a positive correlation of L_radio proportional to L_X-ray^(0.67+/-0.12) . Our simultaneous results differ from this relation by more than 11 sigma, indicating that a separate mode of accretion and ejection may operate in this system. A review of the literature shows that the inverse correlation seen in NGC 4051 is seen in three other black hole systems, all of which accrete at near 10% of their Eddington luminosity, perhaps suggesting a distinct mode of disk-jet coupling at high Eddington fractions. We discuss our results in the context of disk and jets in black holes and accretion across the black hole mass scale.