Multi-Frequency Study of a Radio Source at the Centre of the Galaxy Cluster Abell S1111

Active Galactic Nuclei (AGN) are among the most powerful phenomena in the Universe. They play a crucial role in the formation and evolution of galaxies and, in the most powerful cases, in shaping the properties of galaxy clusters. In this work, I present a study of the BL Lac object PKS 2316-423, located at the centre of the galaxy cluster Abell S1111, using MeerKAT L-band observations. Despite its classification as a blazar, this source exhibits a complex morphology with several features typical of FR I radio galaxies. It hosts a bright, compact core together with very diffuse and filamentary extended emission (∼400 kpc), revealed thanks to the high sensitivity and resolution of MeerKAT. Through in-band spectral mapping, I determined the spectral index distribution with unprecedented resolution. The spectrum steepens from α ≈ −0.2 in the core to α ≈ −1.8 in the outermost regions of the lobes (Sν ∝ να with Sν being the flux density). Fitting a Jaffe–Perola model to these results yields radiative ages ranging from ∼25 to 120 Myr. A polarimetric analysis provides further insight into the source properties and its interaction with the surrounding intracluster medium. Rotation measure synthesis reveals evidence of the Laing–Garrington effect, contributing to the characterization of the source and offering a means to constrain the strength and structure of the magnetic field in the intervening environment.