Dark matter is focused on by Antarctic research

Gravitational lensing diagrams from preliminary data are more promising in detail.

Argonne is part of a multi-agency effort to probe the sky for clues about the origin and nature of our universe.

For more than five years, scientists at the South Pole Telescope in Antarctica have been observing the sky with an improved camera. An expanded view of the universe captures the light left over from the early creation of the universe. Now the researchers are analyzing the initial batch of data and publishing the details in the journal Physical examination d. The results of this limited dataset point to even more powerful future insights into the nature of our universe.

Breakthroughs in Cosmic Microwave Background Analysis

Located at the National Science Foundation's Amundsen-Scott South Pole Station, the telescope received a new camera called SPT-3G in 2017, which was built in 2017 and is now operational. University of Chicago.

fitted 16,000 detectors — 10 times larger than its predecessor — SPT-3G is central to multi-institutional research led as part of Argonne National Laboratory. The goal is to measure faint light called the cosmic microwave background. The Cosmic Microwave Background then glows big bangAlmost 14 billion years ago when the universe exploded from a point of energy.

The cosmic microwave background – the oldest light in the universe – has traveled vast distances before reaching us. During its extended journey, gravitational forces from massive cosmic systems bent its path before it was captured by the South Pole Telescope. Credit: Zhaodi Pan/Argone National Laboratory

„The CMP is a treasure trove for cosmologists,” said Jati Pan, lead author of the paper and a Maria Gobert Meyer Fellow at Argonne. „Its subtle variations in temperature and polarity provide a unique window into the universe's infancy.

Gravitational Lensing and Dark Matter Insights

Paper in Physical examination d Provides the first CMB gravitational lensing measurements from SPT-3G. Gravitational lensing occurs when the universe's vast web of matter distorts the CMB as it travels through space. If you place the curved bottom of a wine glass next to a book, the glass will distract your view of the words behind it. Similarly, material in the telescope's line of sight forms a lens that bends the CMP light and our view of it. Albert Einstein described this warping in the fabric of spacetime in his general theory of relativity.

“The CMP is a treasure map for cosmologists. Its subtle variations in temperature and polarity provide a unique window into the universe's infancy. – Zhaodi Pan, Maria Goeppert Mayer Fellow at Argone

Measurements of that decay hold clues to mysteries like the early universe and dark matter, an invisible component of the universe. „Detecting dark matter is tricky because it doesn't interact with light or other electromagnetic radiation. Currently, we can only observe it through gravitational interactions,” Pan said.

Scientists have been observing the CMB with telescopes on the ground and in space since its discovery in the 1960s. Although the new analysis uses only a few months of SPT-3G data from 2018, the measurement of gravitational lensing is already competitive in the field.

„One of the most exciting parts of this study is that when we started making observations with SPT-3G, it basically came as a result of running the data — and the result was already great,” said Argonne and physicist Amy Bender. Paper co-author. „We still have five years of data that we're analyzing now, so it's indicative of what's to come.”

Promising future research directions

The dry, stable atmosphere and remote location of the South Pole Telescope create as little interference as possible when hunting CMB patterns. However, data from the highly sensitive SPT-3G camera contains contamination from the atmosphere, as well as from our own galaxy and extraterrestrial sources. Analyzing a few months of data from SPT-3G can take years, as researchers must verify the data, filter out noise, and interpret the measurements. They used a dedicated cluster, a group of computers, at the Argonne Laboratory Computer Resource Center to run some of the calculations for the research.

„We found that the lensing patterns observed in this study are well explained by general relativity,” Pan said. „This suggests that our current understanding of gravity holds true for these large scales. The results also strengthen our current understanding of how structures of matter form in our universe.

SPT-3G lensing maps from additional years of data will also help explore the idea that cosmic inflation, or the early universe, underwent rapid exponential expansion. Pan noted that cosmic inflation is „another cornerstone of cosmology,” and scientists are hunting for early signs. Gravitational waves and other direct proofs of this theory. The presence of gravitational lensing introduces interference with inflation seals, necessitating the removal of such contamination, which is calculated using precise lensing measurements.

Some results from the new SPT-3G data will reinforce existing knowledge, while others will raise new questions.

„Each time we add more data, we find more things we don't understand,” said Bender, who holds a joint appointment at the University of Chicago. „As you peel back the layers of this onion, you learn more and more about your instrument and your scientific measurement of the sky.”

Little is known about the invisible elements of the universe, and any understanding is crucial, Pan said: “The more we learn about the distribution of matter, the closer we understand its nature and its role in creating the universe we live in. Today.”

Reference: “Measurement of Gravitational Lensing of the Cosmic Microwave Background Using SPT-3G 2018 Data” by 12 December 2023, Physical examination d.
DOI: 10.1103/PhysRevD.108.122005

This work was funded by the National Science Foundation's Polar Program Office and the DOE Office of Science's High Energy Physics Program. The scientific analysis was led by Pan in close collaboration with lead co-authors WL Kimmy Wu and Federico Bianchini (SLAC National Lab) and the SPT-3G collaboration. Along with Bender and Pan, Argonne-affiliated co-authors are Lindsey Blim, Karen Byram, John Carlstrom, Faustin Carter (Argonne alumnus), Thomas Cecil, Clarence Song, Junjia Ding (Argonne alumnus), Riccardo Gualtieri (Argonne-Argonne), Hosemann (Argonne Alumni), Jason Henning (Argonne Alumni), Florian Kerusorre, Trupti Gyre (Argonne Alumni), Steve Kuhlmann, Valentin Novosat, John Pearson, Christian Posada (Argonne Yelodingmi Vangon, Vorenschlodingminus),