Astronomy Tea Talk

Ultraluminous X-ray sources (ULXs) provide unique laboratories for studying extreme accretion onto compact objects, offering key insights into fundamental problems in modern astrophysics, such as the growth of supermassive black holes in the early Universe. Thanks to the capabilities of current-generation X-ray observatories, particularly XMM-Newton and NuSTAR, the field has undergone significant progress over the past decade. Despite these advances, several fundamental questions remain open: How do ULXs exceed the Eddington limit? What is the nature of their compact accretors? And what drives their extreme variability? In this talk, I will review the main observational phenomenology of ULXs, present recent results obtained by my collaborators and myself, and outline possible directions for future research.