MRC B0319-454: Probing the large-scale structure with a giant radio galaxy

TL;DR

This study explores how the large-scale galaxy distribution influences the morphology of a giant radio galaxy, suggesting that such galaxies can probe the intergalactic medium and its effects on radio structure evolution.

Contribution

It provides new high-sensitivity radio observations and models the interaction between radio galaxy morphology and surrounding large-scale structure, highlighting the role of intergalactic gas and gravity.

Findings

Galaxy density gradients align with radio asymmetries.

Radio structures are influenced by ram-pressure from intergalactic gas.

Giant radio galaxies can probe the warm-hot intergalactic medium.

Abstract

We present an investigation of the relationships between the radio properties of a giant radio galaxy MRC B0319-454 and the surrounding galaxy distribution with the aim of examining the influence of intergalactic gas and gravity associated with the large-scale structure on the evolution in the radio morphology. Our new radio continuum observations of the radio source, with high surface brightness sensitivity, images the asymmetries in the megaparsec-scale radio structure in total intensity and polarization. We compare these with the 3-D galaxy distribution derived from galaxy redshift surveys. Galaxy density gradients are observed along and perpendicular to the radio axis: the large-scale structure is consistent with a model wherein the galaxies trace the ambient intergalactic gas and the evolution of the radio structures are ram-pressure limited by this associated gas. Additionally, we have modeled the off-axis evolution of the south-west radio lobe as deflection of a buoyant jet backflow by a transverse gravitational field: the model is plausible if entrainment is small. The case study presented here is a demonstration that giant radio galaxies may be useful probes of the warm-hot intergalactic medium believed to be associated with moderately over dense galaxy distributions.