Nuclear properties of Brightest Cluster Galaxies: results and new observations for two peculiar cases

TL;DR

This study analyzes the nuclear properties of Brightest Cluster Galaxies, revealing complex core structures, a possible dichotomy based on cluster cooling properties, and recurrent activity, supported by new VLBA observations of two peculiar cases.

Contribution

It provides the first detailed parsec-scale radio observations of BCGs in cool-core and non-cool-core clusters, highlighting structural differences and recurrent activity.

Findings

Cool-core BCGs tend to have two-sided jets, while non-cool-core BCGs have one-sided jets.

Recurrent activity is observed in BCGs within cool-core clusters.

New VLBA data for two peculiar BCGs are presented and discussed.

Abstract

We present here our results on a complete sample of Brightest Cluster Galaxies (BCGs) in nearby Abell Clusters (distance class <3). Combined with data from the literature, we provide parsec scale information for 34 BCGs. We found that also radio loud BCGs have core structures very complex (e.g. 4C 26.42 in Abell 1795). Moreover, we noted 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 is caused by the interplay between the jets and the surrounding medium. Evidence of recurrent activity is also found in BCGs in cool-core clusters. For two peculiar cases of BCGs (IC 712 in Abell 1314 and NGC 6047 in Abell 2151) we asked and obtained new VLBA observations a 1.6 GHz. We discuss them here for the first time.