The surveys will address the following main science topics:

  • Discovery of more than 100000 X-ray selected clusters of galaxies. Galaxy clusters are the largest gravitationally bound structures in the universe. The investigation of  spatial distribution and cosmic evolution of the eROSITA cluster sample will  enable us to measure the  cosmological parameters with improved accuracy  and help to understand the properties of Dark Energy.
  • Detection of about 3 Million Active Galactic Nuclei (AGN). Active galaxies are the most luminous objects in the Universe and are powered by accretion of matter onto a supermassive Black Hole in their center. The sheer size of the eROSITA AGN  catalogue will allow to study the evolution and spatial clustering of AGN with unprecedented detail. Due to its all-sky coverage eROSITA will be able to find very rare populations of AGN such as the most luminous and distant Quasars at redshifts up to z=6 and beyond. The observations at X-ray energies of up 10 keV allow  the detection of the elusive AGN populations that are obscured by gas and dust surrounding the nucleus.
  • Discovery and study of more than 10000 X-ray sources powered by compact stellar objects (White Dwarfs, Neutron Stars and Black Holes) in our galaxy. The all-sky coverage of eROSITA and the ability to penetrate  gas and dust in the plane of the Milky Way will yield a full census of compact galactic objects. The 8 times repeated scanning of the entire sky will help to investigate  the often variable and transient  nature of this object class.
  • Detection of X-rays from up to 500 000 galactic stars. The data will be used to study the X-ray emission processes in all classes of stars and to investigate the relation of X-ray emission in relation to stellar parameters as mass and rotation.

A detailed description of the eROSITA science case can be found in the eROSITA Science Book (PDF 19 Mb).


The AIP contributes to the development of the eROSITA Scientific Analysis Software System (eSASS) and to the design and manufacturing of mechanical components. AIP scientists also  take part in the German eROSITA  science working groups  preparing for the scientific exploitation of the mission.


eROSITA partner institutes (external links):