Radio galaxies interacting with gas motions in dense environments
Radio galaxies in galaxy groups and clusters can be significantly affected by the interaction with the surrounding medium. In particular, recent low-frequency observations have unveiled an increasing number of tailed AGN with peculiar filamentary and distorted morphologies in these dense environments. These structures probe how dynamical motions in the thermal gas can disturb the evolution of radio sources and provide a laboratory to study the process of enrichment of relativistic electrons and magnetic fields in groups and clusters. In this talk, I will present results of recent highly sensitive observations at low-frequency performed with LOFAR and the uGMRT of AGN living in dense environments that show evidence of ongoing interaction with the thermal gas, as confirmed by X-ray observations. I will also provide evidence for the presence of filaments of radio emission with very steep spectrum which are likely related to remnant fossil plasma ejected by previous AGN outbursts that is being re-energized through compression processes. These observational results will be placed into the context of the interplay between thermal and non-thermal components and of the life cycle of relativistic electrons in dense environments.