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Physicists explore dark energy, opening new window to dark energy

Physicists explore dark energy, opening new window to dark energy

A celestial map showing the densities of galactic clusters, galaxies, and cosmic matter above the part of the sky surveyed by dark energy observations. The left panel shows the density of the galaxies in that part of the sky, while the center panel shows the density of matter and the right shows the galaxy cluster density. Red areas are denser and blue areas are less dense than average.Credits: Chun-Hao To / Stanford University, SLAC National Accelerator Laboratory.

The universe is expanding at an ever-increasing rate, and while no one is sure why, researchers with the Dark Energy Survey (DES) at least have a strategy for figuring it out: Diffuse galactic matter, and Galaxy clusters to better understand what is going on

Achieving that goal becomes a hassle. But now a team led by researchers at the Department of Energy’s SLAC National Accelerator Laboratory, Stanford University and the University of Arizona have come up with a solution. Their analysis was published on April 6 in Physical review letterIt provides a more accurate estimate of the mean density of matter, as well as its tendency to clump, two key factors that help physicists examine the nature of dark matter and dark energy, which is matter. The mysteries that make up the vast majority of the universe.

“It’s one of the best constraints from one of the best datasets to date,” said Chun-Hao To, lead author of the new paper and graduate student at SLAC and Stanford, who works with the Kavli Institute for Particle Astrophysics. and Cosmology Director Risa Wechsler

First goal

When DES began mapping the sky in 2013, the goal was to collect four types of data: distance to certain types of supernova or exploding stars. Distribution of matter in the universe Distribution of galaxies And distribution of galactic clusters Each of them tells researchers something about how the universe is evolving over time.

In principle, the scientists would combine the four data sources to improve their estimates. But there are obstacles: The distribution of matter, galaxies and galaxy clusters are all closely related. If researchers don’t take these relationships into account, they’ll end up with It is “double-count”, weighting too much on some data and not enough on others, To said.

To avoid handling all of this information incorrectly, Elisabeth Krause, an astrophysicist at the University of Arizona and colleagues, has developed a new model that can appropriately describe the connection in the distribution of all three quantities: matter. Galaxies and galaxy clusters In doing so, they were able to create an initial analysis to properly combine these different datasets to learn about dark matter and dark energy.

Revision of the estimate

Adding that model to a DES analysis has two consequences. First of all, measuring the distribution of galactic matter and galactic clusters often results in different types of errors. Combining all three measurements makes it easier to identify such errors, making the analysis more efficient. Second, the three measurements differed in their susceptibility to mean density of matter and coagulation. As a result, combining the three can improve the accuracy with which DES is able to measure dark matter and dark energy.

In the new paper, To, Krause and colleagues used their new method in the first year of DES data and increased the accuracy of previous estimates for density and concentration of matter.

The team was now able to combine galactic matter and galaxy clusters simultaneously in their analysis, adding the supernova data would be fairly straightforward since that type of data was not closely related to the other three.

“The next step immediately,” he said, “is to apply the machine to DES Year 3 data, which covers more than three times the sky.” But the new data will require additional efforts to improve the model to reflect the higher quality of the newer data, To said.

“This analysis is exciting,” Wechsler said. “I expect it to set a new standard in which we will be able to analyze data and learn about dark energy from large-scale surveys, not just for DES but also looking forward to it.” The incredible data we can get from exploring the Vera Rubin Observatory’s legacy of space and time in a few years. ”

The smallest galaxies in our universe make dark matter more light.

More information:
C. to Others, Results of the Dark Energy Survey in Year 1: Cosmological limitations from cluster abundance, weak vision, and galactic affinity. Physical review letter (2021). DOI: 10.1103 / PhysRevLett.126.141301

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Reference: Physicists exploring dark energy open a new window into dark energy (2021, April 6) .Retrieved April 6, 2021 from https://phys.org/news/2021-04-dark-energy-survey-physicists-window.html.

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