Testing the existence of event horizons against rotating reflecting surfaces Joost de Kleuver, Thomas Bronzwaer, Heino Falcke, Ramesh Narayan, Yosuke Mizuno, Oliver Porth and Hector Olivares A&A, 689 (2024) A197 Published online: 13 September 2024 DOI: 10.1051/0004-6361/202348489