The first massive galaxy groups in the Universe are predicted to have formed when the Universe was less than 4 billions years old (redshift > 2). Baryonic physics, like stellar and active galactic nuclei (AGN) feedback in this very active epoch, are expected to have left a strong imprint on the thermo-dynamic properties of these early galaxy groups. Therefore, observations of these groups are key to constrain the relative importance of these physical processes. However, current instruments are not sensitive enough to detect them easily and characterize their hot gas content. In this work, the astronomers quantified the observing power of the Advanced Telescope for High ENergy Astrophysics (Athena), the future large X-ray observatory of the European Space Agency (ESA), for discovering and characterizing early galaxy groups in the early Universe.
Read more in the Athena X-ray Observatory web-page: