eROSITA’s First View on Hot Baryons of the Universe
Abstract
Successfully launched in July 2019, eROSITA, the German-built telescope array operating between 0.2-8 keV on board the Russian-German Spectrum-RG (SRG) mission, provides a unique imaging, spectroscopic, and timing capability. By performing eight all-sky surveys, each lasting half a year in the next four years, eROSITA will deliver the largest catalogs of cluster of galaxies. Clusters of galaxies trace the highest peaks in the cosmic density field and offer an independent and powerful probe of the growth of structure and their abundance is strongly dependent on the underlying cosmology. In the near future, the availability of the final eROSITA All-Sky Survey catalogues with more than 100,000 clusters will put us on the verge of a breakthrough in precision cosmological measurements. At the depth of the final All-Sky Survey, the eROSITA Final Equatorial Survey (eFEDS), executed during the Performance Verification phase, have provided a sneak preview on the cluster science that will be achieved by 2024. I will summarise these first results on the clusters of galaxies and galaxy groups detected in the eFEDS field.