Two Million X-ray Sources Reveal New High-Energy Cosmos
Astronomers’ second public data release from the German-led eROSITA X-ray telescope, DR2, catalogs nearly 2 million X-ray sources—over 1.9 million point-like objects (mostly active supermassive black holes and Milky Way stars) and about 64,000 extended sources (galaxy clusters and remnants). By linking X-ray detections to optical/IR counterparts, DR2 provides the most comprehensive, uniform view of the high-energy universe to date, enabling robust studies of black-hole growth, galaxy evolution, and large-scale cosmic structures; a future DR3 is planned for 2028, effectively nearly doubling our view of the high-energy cosmos.