High-frequency radio properties of central AGNs in cluster environments

We present K-band (22 GHz) properties of 10 central AGNs in galaxy clusters of various dynamic states. The data were obtained using the Korean VLBI Network (KVN) with a goal to study how the AGN hosted by the central cluster galaxy interacts with the cluster core while undergoing feedback. In KVN single-dish observations, 9 out of 10 targets are detected. Using our K-band flux and archival low-frequency radio data, we evaluate spectral indices of the sample. We find a rough trend that central AGNs in the cluster with shorter cooling timescale show a more flat radio spectrum. This result is suggestive of young synchrotron age of the AGNs located in the cluster with a cool core. High resolution KVN VLBI follow up observations indicate some hints of the presence of parsec-scale jets only in the cool core cluster AGNs. To-gether with our finding from KVN single-dish observations, the parsec-scale jet morphology of the sample suggests that the AGNs in cool-core clusters are more recently (re)activated compared to their counterparts in non cool-core clusters.