A powerful (and likely young) radio-loud quasar at z = 5.3 S. Belladitta, A. Moretti, A. Caccianiga, D. Dallacasa, C. Spingola, M. Pedani, L. P. Cassarà and S. Bisogni A&A, 669 (2023) A134 Published online: 24 January 2023 DOI: 10.1051/0004-6361/202243855