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Dark energy investigation physicist opens a new window for dark energy



Dark energy investigation physicist opens a new window for dark energy

The sky map shows the density of galaxy clusters, galaxies, and matter in the universe in part of the sky observed by dark energy surveys. The left panel shows the density of galaxies in that part of the sky, while the middle panel shows the density of matter, and the right panel shows the density of galaxy clusters. The density of the red area is higher than average, and the density of the blue area is lower than average.Image source: Chunchun/Stanford University, SLAC National Accelerator Laboratory

The universe is expanding at a faster and faster rate. Although no one knows why, the Dark Energy Survey (DES) researchers have at least one solution: combine the measurement results of the distribution of matter, galaxies, and galaxies into clusters of galaxies. Get a good understanding of what is happening.

Achieving this goal is very tricky, but now a team led by researchers from the Department of Energy’s SLAC National Accelerator Laboratory, Stanford University and the University of Arizona has proposed a solution.The results of their analysis were published on April 6th Medical letterThe average density of the substance and its tendency to agglomerate can be more accurately estimated. These two key parameters can help physicists explore the nature of dark matter and dark energy, which are the most mysterious matter that constitutes the vast majority of the universe.

To Chun-Hao To, the lead author of this new paper, a graduate student from SLAC and Stanford University, and the director of Kavli Particle Astrophysics and Cosmology, said: “This is one of the best constraints in the best data set so far. One.” Risa Wechsler (Risa Wechsler).

Early goals

When DES set out to map one-eighth of the sky in 2013, the goal was to collect four types of data: the distance to certain types of supernovae or exploding stars; and the distribution of matter in the universe; the distribution of galaxies; and galaxy clusters Distribution. Everyone tells researchers about how the universe has evolved over time.

Ideally, scientists would put all four data sources together to improve their estimates, but there is one obstacle: the distribution of matter, galaxies, and galaxy clusters are all closely related. To said that if researchers do not consider these relationships, they will end up “double counting”, imposing too much weight on some data and not enough weight on other data.

In order to avoid processing all this information, astrophysicist Elisabeth Krause (Elisabeth Krause) and colleagues at the University of Arizona have developed a new model that can correctly explain the distribution of the three quantities of matter, galaxies and galaxy clusters. the relationship between. By doing so, they were able to conduct the first analysis ever to correctly combine all these different data sets to understand dark matter and dark energy.

Improve estimates

To said that adding the model to the DES analysis has two effects. First, the measurement of the distribution of matter, galaxies and galaxy clusters often introduces different types of errors. Combining all three measurements makes it easier to identify any such errors, making the analysis more reliable. Secondly, these three measurement methods have different sensitivity to the average density of the substance and its agglomeration. As a result, the combined use of these three methods can improve the accuracy of DES measuring dark matter and dark energy.

In the new paper, To, Krause and colleagues applied their new method to the first year of DES data and improved the accuracy of previous estimates of material density and clumping.

Too said that since the research team can simultaneously incorporate matter, galaxies, and galaxy clusters into their analysis, it will be relatively simple to add supernova data because this type of data is not closely related to the other three data.

He said: “The urgent next step is to apply this machine to DES Year 3 data, which has three times the coverage of the sky.” This is not as simple as it sounds: To says that although the basic idea is the same, But the new data will require extra effort to improve the model to keep up with the new data of higher quality.

Wexler said: “This kind of analysis is really exciting.” “I hope it will set a new standard for the way we analyze data and understand dark energy from large surveys, which is not only applicable to DES, but also hopefully We can get incredible data from the old-style surveys of the Vera Rubin Observatory on the temporal and spatial changes in a few years.”


The smallest galaxy in our universe brings more dark matter into the light


More information:
C. To et al., “Results of the First Year of the Dark Energy Survey: Cosmological Constraints on Cluster Abundance, Weak Lens, and the Correlation of the Milky Way” Medical letter (2021). DOI: 10.1103 / PhysRevLett.126.141301

Provided by SLAC National Accelerator Laboratory



Citation: Dark energy survey physicists opened a new window for dark energy (April 6, 2021), retrieved from https://phys.org/news/2021-04-dark-energy-survey-physicists-window.html April 6, 2021

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