DESI finishes observations for largest 3D map of universe

An error occurred while preparing your download

DESI finishes observations for largest 3D map of universe

Five-year mission completed as dark matter research expands

In pursuit of understanding the role dark energy plays in complex physics, researchers have marked completion of a major milestone: successfully surveying the entire target area in the Dark Energy Spectroscopic Instrument (DESI)'s 3D map of the universe.

Finished ahead of schedule and armed with vastly more data than expected, researchers plan to use DESI's map, which is the largest high-resolution 3D construct of the universe ever made, to explore dark energy, the fundamental ingredient that makes up about 70% of the cosmos.

In the five years since DESI began collecting data, the survey has observed more than 47 million galaxies and quasars and 20 million stars, and its results have already revealed much about the structure and evolution of the universe, said Paul Martini, the instrument scientist during DESI construction and commissioning and a professor of astronomy at The Ohio State University.

"DESI has been a superb international collaboration, and its incredibly fruitful scientific results are a leading example of its impact on the broader scientific community," he said.

DESI's quest to understand dark energy is a global endeavor. The international experiment brings together the expertise of more than 900 researchers (including 300 PhD students) from over 70 institutions and is managed by the Department of Energy's Lawrence Berkeley National Laboratory. Researchers at Ohio State have been crucial partners to some of DESI's most significant discoveries, from helping analyze the promising first-year results to learning how dark energy continues to evolve in unexpected ways.

"Ohio State made the largest contributions to the instrumentation, operations and analysis infrastructure of any university group in DESI," said Klaus Honscheid, lead scientist of DESI instrument operations and a physics professor at Ohio State. "We are proud of our collaboration's world-leading results on dark energy, as well as pleased with the substantial, international media attention they have received."

Amidst the program's ambitious schedule, the DESI team's ability to complete the survey in five years was challenged more than once, most notably by the Contras wildfire in 2022, which interrupted power and internet infrastructure in the observatory for months. Fortunately, these disruptions were isolated and fixed quickly, said Ashley Ross, lead scientist for the DESI large-scale structure catalogs and an assistant research professor of physics at Ohio State.

"By coming up with creative solutions to address unforeseen problems, the high-quality data we collected each night was carefully and confidently used to obtain the exciting cosmological constraints that DESI is now known for," said Ross.

Now, with this new completed set of data, scientists will have significantly more information to test long-held hypotheses about the balance between dark energy and matter, and their answers may mark a major shift in how we think about our universe and its potential fate.

Having measured cosmological data for six times as many galaxies and quasars as all previous measurements combined, the collaboration plans to immediately begin processing their completed dataset in the coming months, with the first dark energy results from DESI's full five-year survey expected in 2027.

After completing the original five-year mission, DESI plans to continue observations through 2028. This will include expanding its survey to include parts of the sky that are more challenging to observe: Constructing a more detailed map of the cosmos may also make it easier for scientists to study nearby objects like dwarf galaxies and stellar streams, and grant them the ability to paint a much clearer picture of the universe's formation and history, said Honscheid.

But in the meantime, the Ohio State team will continue refining their dark energy measurements by analyzing data gathered during the first three years, and optimize their telescope time and its capabilities to help make exciting new observations.

"A larger survey footprint will greatly improve our constraints on cosmological parameters and improve our dark matter program," said Honscheid. "But these achievements are only possible because the operations team worked incredibly hard to keep the survey progressing."

Other Ohio State contributors to DESI include Matthew Berno, Mikel Charles, Carl Coker, Rebecca Coles, Andrei Cuceu, Xinyi Chen, Mark Derwent, Ann Elliott, Jack Elvin-Poole, Lauren Ennesser, Kevin Fanning, Simon Filbert, Meagan Herbold, Jennifer Johnson, Naim Karacayli, Hui Kong, Claire Lamman, Thomas O'Brien, Daniel Pappalardo, Richard Pogge, Anna Porredon, Michael Rashkovetskyi, Jon Shover, Peter Taylor, Wynne Turner, David Weinberg, Molly Wolfson and Erik Zaborowski.

DESI is supported by the DOE Office of Science and by the National Energy Research Scientific Computing Center, a DOE Office of Science national user facility. Additional support for DESI is provided by the U.S. National Science Foundation; the Science and Technology Facilities Council of the United Kingdom; the Gordon and Betty Moore Foundation; the Heising-Simons Foundation; the French Alternative Energies and Atomic Energy Commission (CEA); the Secretariat of Science, Humanities, Technology and Innovation (SECIHTI) of Mexico; the Ministry of Science and Innovation of Spain; and by the DESI member institutions.

The DESI collaboration is honored to be permitted to conduct scientific research on I'oligam Du'ag (Kitt Peak), a mountain with particular significance to the Tohono O'odham Nation.

More Ohio State News