The role of environment in the observed Fundamental Plane of radio Active Galactic Nuclei

TL;DR

This study investigates how the environment influences the Fundamental Plane of radio AGN, revealing that galaxy halo mass affects AGN properties and their scaling relations, with implications for black hole activity models.

Contribution

It demonstrates that environment-driven selection effects significantly impact the observed Fundamental Plane, suggesting the intrinsic relation is mass-independent when accounting for environment.

Findings

Halo mass correlates with AGN radio and optical properties.

Environment influences the type and luminosity of radio AGN.

Mass scalings are a result of combining different environment-dependent populations.

Abstract

The optical Fundamental Plane of black hole activity relates radio continuum luminosity of Active Galactic Nuclei to [O III] luminosity and black hole mass. We examine the environments of low redshift ($z<0.2$) radio-selected AGN, quantified through galaxy clustering, and find that halo mass provides similar mass scalings to black hole mass in the Fundamental Plane relations. AGN properties are strongly environment-dependent: massive haloes are more likely to host radiatively inefficient (low-excitation) radio AGN, as well as a higher fraction of radio luminous, extended sources. These AGN populations have different radio -- optical luminosity scaling relations, and the observed mass scalings in the parent AGN sample are built up by combining populations preferentially residing in different environments. Accounting for environment-driven selection effects, the optical Fundamental Plane of supermassive black holes is likely to be mass-independent, as predicted by models.