Resolve contamination from confused multiple X-ray binaries

Determine whether individual ultraluminous X-ray candidates in distant or extended galaxies are genuine single ULXs or unresolved blends of multiple luminous X-ray binaries.

Background

The angular resolution of eROSITA can cause multiple luminous X-ray binaries or extended emission regions to be detected as a single point source, artificially increasing the inferred luminosity. Comparisons with host-galaxy star-formation scaling relations suggest that most candidates are unlikely to be produced by diffuse gaseous emission, but those relations cannot distinguish a genuine ULX from a blend of multiple luminous X-ray binaries. Resolving this ambiguity requires higher-resolution imaging or other follow-up observations.