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 Lawrence Berkeley National Laboratory (Berkeley Lab). Ohio State has been a core member of the DESI collaboration for over a decade and includes 12 researchers actively working on the collection and analysis of DESI data.
The collaboration shared their findings in multiple papers that will be posted online and later in a presentation at the American Physical Society's Global Physics Summit in Anaheim, California.
Taken alone, DESI's data is consistent with our standard model of the universe. However, when paired with other measurements, there are mounting indications that the impact of dark energy may be weakening over time and other models may be a better fit. Those other measurements include the light left over from the dawn of the universe; supernovae, or exploding stars; and how light from distant galaxies is warped by gravity.
"These measurements show some evidence that the standard model of cosmology is not the best explanation," said Ashley Ross, lead scientist for the DESI large-scale structure catalogs and a research professor of physics at Ohio State. "We now have multiple datasets that are pointing in this direction, which strengthens our confidence in our results."
While DESI's previous release initially showed a preference for dynamical dark energy, many researchers thought a statistical fluke was a more likely explanation than a major discovery, said Paul Martini, one of the coordinators of the current analysis and a professor of astronomy at Ohio State. "Yet the evidence for dynamical dark energy has gotten stronger with more data, and it has passed new and tougher tests, so we are more confident and more excited."
In parallel to the DESI analysis, work is going on to plan the next phases of DESI that will follow at the end of the decade as well as for even more powerful instruments that will be built in the future. Besides DESI, other experiments coming online over the next several years will also provide complementary datasets for future analyses.
The DESI collaboration also recently announced that its Data Release 1 (DR1) is now available for anyone to explore. With information on millions of celestial objects, the dataset will support a wide range of astrophysical research by others, in addition to DESI's cosmology goals.
Researchers see hints that dark energy, widely thought to be a "cosmological constant," might be evolving over time in unexpected ways.
New results from the Dark Energy Spectroscopic Instrument (DESI) collaboration, one of the most extensive surveys of the cosmos ever conducted, reveal that the impact of dark energy may be weakening over time - and the standard model of how the universe works may need an update.
This recent finding uses data from the first three years of observations and includes nearly 15 million galaxies and quasars, more than doubling the dataset used in DESI's first analysis, which was presented less than one year ago. It's a major leap forward, improving the experiment's precision with a dataset that is more than double what was used in DESI's first analysis which also hinted at an evolving dark energy.
"Our results are truly remarkable," said Klaus Honscheid, lead scientist of DESI instrument operations and a physics professor at The Ohio State University. "We are seeing even stronger evidence for a fundamental shift in how we think about dark energy."
Research Report:DESI Key Publications
Related Links
Dark Energy Spectroscopic Instrument
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