Quasar radiation transforms the gas in a merging companion galaxy - Sergei Balashev; Pasquier Noterdaeme; Neeraj Gupta; Jens-Kristian Krogager; Françoise Combes; Sebastián López; Patrick Petitjean; Alain Omont; Raghunathan Srianand; Rodrigo Cuellar (Nature, 2025)