New approach into Dark Energy, understanding more about the mysterious force
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Credit: SLAC NATIONAL ACCELERATOR LABORATORY |
The universe is expanding at an ever-increasing rate, and there is no answer to that, why is it expanding?
Dark Energy is thought to be the reason for that. It is totally hypothetical but it is thought to be the reason for causing the universe to expand. And scientists are trying to find this mysterious force to prove its existence, and also to understand how it will work.
Researchers at Dark Energy Survey (DES) had a strategy to figuring it out, by combining the measurements of the distribution of matter, galaxies, and galaxy clusters to understand what going on. Well distribution of galaxies, distribution of galaxies that form structure, and the distortion of light from faraway galaxies by matter that is closer to earth, to be precise.
Now doing so is very tricky to do, but a team lead by researchers at the Department of Energy's SLAC National Accelerator Laboratory, Standford University, and the University of Arizona have come up with a solution. Their analysis published in the Physical Review Letters yields more precise estimates of the average density of matter as well as its propensity to clump together, the key parameters that help physicists probe the nature of dark matter and dark energy.
When DES set out in 2013, to map an eighth of the sky, the goal was to gather four kinds of data: the distances to certain types of supernovae, or exploding stars; the distribution of matter in the universe; the distribution of galaxy clusters. These parameters indicate how the universe has evolved over time. They would put all four data sources together to improve their estimates.
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| Credit: Chun-Hao To/Stanford University, SLAC National Accelerator Laboratory |
The distribution of matter, galaxies, and galaxy clusters are all closely related. If researchers don't take these relationships into account, they will end up "double counting", placing too much weight on some data and not enough on others. To avoid mishandling all this information, To, the University of Arizona Astrophysicist, Elisabeth Krause, and colleagues have developed a new model that could properly account for the connections in the distribution of all three quantities: Matter, Galaxies, and Galaxy Clusters. With that, they were able to produce the first-ever analysis to properly combine all these disparate data sets in order to learn about dark matter and dark energy. They were able to make the data from the first year of DES, more precise than previous estimates for matter's density and clumpiness using the new methods.
Adding that model into the DES analysis has two effects, first measurements of the distribution of the three tend to introduce different kinds of errors. Combining all three measurements makes it easier to identify any such errors, making analysis more robust. Second, the three measurements differ in how sensitive they are to the average density of the matter and its clumpiness. As a result, combining the three can improve the precision with which DES can measure Dark matter and Dark energy.
They are gonna apply the machinery to DES year 3 data which had three times larger sky coverage.
Source: DOI: 10.1103/PhysRevLett.126.141301
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