Non-thermal emission in galaxy groups at extremely low frequency: The case of A1213 T. Pasini, V. H. Mahatma, M. Brienza, K. Kolokythas, D. Eckert, F. de Gasperin, R. J. van Weeren, F. Gastaldello, D. Hoang and R. Santra A&A, 693 (2025) A94 Published online: 07 January 2025 DOI: 10.1051/0004-6361/202452006