Population in the detected source catalog. The total number of sources in the cleaned catalog of the eRASS1 simulation is 901 812. The number of extended sources is 5615. Top panels: number of sources in the full catalog and fractions of the population classes in linear scale as a function of minimum detection likelihood. Central panels: number of sources and fractions of the population classes in linear scale in the extent-selected sample (EXT_LIKE >= 6) as a function of minimum detection likelihood. Bottom panels: population in the source catalog and fractions of the population classes in linear scale as a function of minimum extension likelihood. Lines of different colors show the classes defined in Sect. 3. The dashed-dotted lines denote sources that are not contaminated by photons of a secondary source (no blending), the dashed ones identify sources contaminated by a point source, and the dotted ones show sources blended with a cluster.