Parsec-scale Properties of Brightest Cluster Galaxies

TL;DR

This study uses VLBI observations to analyze the parsec-scale radio structures of Brightest Cluster Galaxies, revealing a potential link between jet morphology and cluster core properties, indicating different jet-environment interactions.

Contribution

It provides the first comprehensive parsec-scale radio analysis of a complete BCG sample, highlighting a possible dichotomy in jet structures related to cluster core types.

Findings

BCGs in cool core clusters often have two-sided jets.

BCGs in non cool core clusters predominantly show one-sided jets.

Evidence of recurrent activity in BCGs within cool core clusters.

Abstract

We present new VLBI observations at 5 GHz of a complete sample of Brightest Cluster Galaxies (BCGs) in nearby Abell Clusters (distance class <3). Combined with data from the literature, this provides parsec-scale information for 34 BCGs. Our analysis of their parsec scale radio emission and cluster X-ray properties shows a possible dichotomy between BCGs in cool core clusters and those in non cool core clusters. Among resolved sources, those in cool core clusters tend to have two-sided parsec-scale jets, while those in less relaxed clusters have predominantly one-sided parsec-scale jets. We suggest that this difference could be the result of interplay between the jets and the surrounding medium. The one-sided structure in non cool core clusters could be due to Doppler boosting effects in relativistic, intrinsically symmetric jets; two-sided morphology in cool core clusters is likely related to the presence of heavy and mildly relativistic jets slowed down on the parsec-scale. Evidence of recurrent activity are also found in BCGs in cool core clusters.