New Insights into Galaxy Cluster Interactions in the Shapley Supercluster

Recent observations of the A3528 cluster complex in the Shapley Supercluster have revealed significant findings regarding the interactions between galaxy clusters and their effects on radio galaxies. The study, titled "Cosmic dance in the Shapley Concentration Core II. The uGMRT-MeerKAT view of filaments in the brightest cluster galaxies and tailed radio galaxies in the A3528 cluster complex," was conducted by G. Di Gennaro and a team of researchers.

The research focused on how minor mergers among galaxy clusters influence the evolution of radio galaxies and their ability to re-accelerate relativistic electrons in the intracluster medium (ICM). Utilizing data from the uGMRT and MeerKAT telescopes, the team produced images and spectral index maps across a broad frequency range.

Key findings include:

• Detection of faint diffuse radio emissions associated with the radio galaxies in the A3528 complex.
• Filaments of diffuse radio emissions extending approximately 200-400 kpc from the brightest cluster galaxies (BCGs) in A3528S and A3532.
• The spectral index of these filaments was found to be steep and nearly constant, suggesting non-standard plasma aging processes.
• Identification of a potential radio mini-halo surrounding the BCG in A3528S, with a radio tail measuring around 300 kpc in length.

The study links the presence of extended radio emissions to the effects of minor mergers, supported by increasing X-ray fluctuations corresponding with the radio emissions in A3528S. These findings contribute to the understanding of how minor mergers can rejuvenate plasma from radio galaxies, despite the lower energy involved compared to major mergers. This research adds to the growing body of knowledge regarding the dynamics of galaxy clusters and their interactions within superclusters.

The full paper can be accessed at arXiv:2408.14142.