EQUALS Survey Uses ESPRESSO to Unlock Secrets of the Early Universe

A major new astronomical survey, called EQUALS, has begun using the ESPRESSO instrument to study distant gas clouds in the universe. Led by researchers Trystyn Berg, Valentina D’Odorico, and Elisa Boera, the project will examine how these gases interact with light from quasars—some of the brightest objects in space. The ESPRESSO Quasar Absorption Line Survey (EQUALS) focuses on analysing metal absorption lines in quasar light. By studying these lines in detail, scientists hope to uncover how galaxies spread metals into the intergalactic medium (IGM) over time. The survey will also search for extremely metal-poor absorbers, which could reveal key properties of the universe’s first stars.

ESPRESSO’s high-resolution capabilities play a crucial role in this work. The instrument allows for precise measurements of absorption features, helping researchers map the IGM’s structure and evolution. The team plans to observe a large sample of quasars, ensuring statistically robust results about the gas filling the space between galaxies. Beyond mapping the IGM, EQUALS aims to refine cosmological models. The project will contribute to more accurate measurements of fundamental cosmological parameters. It will also test theories about warm dark matter by analysing the Lyman-alpha forest—a pattern of hydrogen absorption lines in quasar spectra. These findings are expected to improve simulations of galaxy formation and early stellar processes.

The EQUALS project will produce a detailed map of the intergalactic medium, offering insights into its composition and changes over billions of years. Its data on metal distribution and dark matter properties will support future studies on galaxy evolution and the conditions of the early universe.