The analysis was carried out within the Dark Energy Survey (DES) , an international collaboration that studies the nature of dark energy by mapping hundreds of millions of galaxies and tracing the expansion history of the Universe. The study combines the final DES measurements of baryon acoustic oscillations and supernova distances to test cosmological expansion models with high precision.

While the standard ΛCDM model continues to provide an excellent overall description of the data, the results reveal mild tensions between different observational probes. These differences are not statistically conclusive but highlight the increasing sensitivity of modern cosmological measurements and the importance of carefully assessing both systematic effects and possible extensions of the model.

Researchers from IFAE’s Observational Cosmology Group, including Simon Samuroff and Ramon Miquel, contributed to the analysis and interpretation of the results, drawing on their expertise in large-scale structure, galaxy surveys, and cosmological parameter estimation. The work reflects the group’s long-standing involvement in the Dark Energy Survey and its broader effort to test fundamental cosmological models using precision data.

Future surveys and upcoming datasets will further improve these tests, helping to determine whether the observed tensions persist and what they may reveal about the physical processes governing the expansion of the Universe.

About the Dark Energy Survey

The Dark Energy Survey (DES) is an international collaboration of more than 400 scientists from 25 institutions in seven countries. The project is led by Fermi National Accelerator Laboratory (Fermilab), America’s premier national laboratory for particle physics and accelerator research, managed by the Fermi Forward Discovery Group for the U.S. Department of Energy Office of Science.

Spain was the first international partner to join the United States in founding the DES project in 2005. Spanish participation includes three institutions: two based in Barcelona — the Institute of Space Sciences (ICE-CSIC) and IFAE — and one in Madrid, the Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), as well as researchers from the Instituto de Física Teórica (IFT/CSIC-UAM).

For more information about the project, visit the Dark Energy Survey website: https://www.darkenergysurvey.org/es/