#AthenaNuggets 42 proposes the study of quasars as new cosmic tracers. These astronomical objects will allow the measurement of the expansion rate of the Universe up to z~10, i.e., when the Universe was less than 500 million years old. The role of the Athena will be fundamental to assess the state-of-the-art cosmological models, due to its accuracy in the determination of distant quasar X-ray fluxes.

Read more in Athena X-ray observatory website.