CfA Astronomers Play Key Role in New Dark Energy Results
DESI maps distant objects to study dark energy. The instrument is installed on the 4-meter Mayall Telescope at the Kitt Peak National Observatory in Arizona, shown here beneath star trails.
Credit: KPNO/NOIRLab/NSF/AURA/B. Tafreshi
Cambridge, MA - New results from the Dark Energy Spectroscopic Instrument (DESI) collaboration, using the largest 3D map of our universe ever made, have tracked dark energy’s influence over the past 11 billion years. Researchers see hints that dark energy, widely thought to be a “cosmological constant,” might be evolving over time in unexpected ways.
These results were announced today in a press release from the Lawrence Berkeley National Laboratory (Berkeley Lab) that is available here.
Combining the DESI data of over 14 million galaxies and quasars with the results from other experiments, scientists have stronger evidence that the impact of dark energy may be weakening over time, arguing that the standard model of how the universe works may need an update.
DESI tracks dark energy’s influence by studying how matter is spread across the universe. Events in the very early universe left subtle patterns in how matter is distributed, a feature called Baryon Acoustic Oscillations (BAO). That BAO pattern acts as a standard ruler, with its size at different times directly affected by how the universe was expanding. Measuring the ruler at different distances shows researchers the strength of dark energy throughout history. DESI’s precision with this approach is the best in the world.
The Center for Astrophysics | Harvard & Smithsonian (CfA) researchers, led by Harvard professor Daniel Eisenstein and his group, were crucial contributors to the DESI collaboration in multiple ways, including co-developing algorithms and simulations that led to the latest results. Cristhian Garcia Quintero is one of the collaboration leads on the cosmological interpretations of the results. Michael Rashkovetskyi performed calculations that are critical for the distance measurements. Claire Lamman is the co-chair of the DESI education and public outreach committee and helped create the visual material for the public. Eisenstein served as co-spokesperson of the collaboration 2014 to 2020.
DESI is an international experiment with more than 900 researchers from over 70 institutions around the world and is managed by the U.S. Department of Energy’s Berkeley Lab. The collaboration shared their findings today in multiple papers that will be posted on the online repository arXiv and in a presentation at the American Physical Society’s Global Physics Summit in Anaheim, California.
Alongside unveiling its latest dark energy results at the APS meeting today, the DESI collaboration also announced that its Data Release 1 (DR1) is now available for anyone to explore. With detailed information on many millions of celestial objects, the dataset will support a wide range of astrophysical research at CfA and elsewhere. In addition to contributing to DESI’s cosmology goals, CfA researchers are active in using DESI to study galaxy evolution, the cosmic web, and the structure of the Milky Way galaxy. The DESI survey continues each clear night, extending its map of the cosmos and giving astronomers a better and better view of the surprising physics of the Universe.
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