The origin of the soft excess in the luminous quasar HE 1029-1401 B. Vaia, F. Ursini, G. Matt, D. R. Ballantyne, S. Bianchi, A. De Rosa, R. Middei, P. O. Petrucci, E. Piconcelli and A. Tortosa A&A, 688 (2024) A189 Published online: 21 August 2024 DOI: 10.1051/0004-6361/202449524