New Measurement Captures Clearer Picture of Our Galaxy and Beyond

A small observatory nestled in the Andes mountains of northern Chile has produced remarkable maps of 75% of the sky, offering a clearer understanding of our galaxy and the universe beyond. This feat, achieved through unique capabilities to track microwave energy fluctuations, marks a significant leap forward in the quest to measure the origin and evolution of the universe with greater precision.

New CLASS polarization sky maps have less noise than the corresponding satellite maps. The direction of polarization is depicted by red and blue while the polarization strength is captured by the depth of color. Gray sections depict parts of the sky that the CLASS telescopes cannot observe due to their geographical location. Credit: Johns Hopkins University

The initiative, spearheaded by the U.S. National Science Foundation Cosmology Large Angular Scale Surveyor (CLASS), led by astrophysicists from Johns Hopkins University, has yielded maps that shed light on the intricate dance of microwave polarization—essentially, how energy waves oscillate in specific directions. These maps, which are soon to be published in The Astrophysical Journal, hold the promise of revolutionizing our comprehension of the universe's history and fundamental physics, from its primordial moments to the formation of galaxies, stars, and planets.

"By scrutinizing the polarization of the cosmic microwave background, astrophysicists can glean insights into the primordial conditions of the universe," explains Tobias Marriage, a professor of physics and astronomy at Johns Hopkins University and co-leader of the team. "These observations allow us to trace back to the earliest epochs, unraveling the cosmic narrative from its inception to the present day."

One of the key achievements of the new CLASS maps lies in their ability to significantly enhance observations by filtering out microwaves emitted by our Milky Way galaxy, thus providing a clearer view of the cosmic microwave background. This residual radiation, a relic of the universe's infancy, offers crucial clues about its early state and evolution over billions of years.

Charles L. Bennett, a Bloomberg Distinguished Professor at Johns Hopkins University, underscores the significance of these findings, noting that they not only refine measurements of the Milky Way's signals but also offer insights into potential sources of circular polarization—a unique form of microwave radiation that could illuminate early universe phenomena.

Nigel Sharp, a program director in NSF's Division of Astronomical Sciences, emphasizes the importance of such endeavors in advancing our understanding of the cosmos. He praises the new measurements for providing essential large-scale details within the cosmic background radiation, highlighting the remarkable achievement of ground-based instruments in unveiling the universe's secrets.

Unlike space missions, which have their limitations, the research conducted by the CLASS observatory opens avenues for more detailed observations with ground-based telescopes, fostering ongoing advancements in instrumentation. Joseph Eimer, lead author of the study and an astrophysicist at Johns Hopkins University, underscores the significance of CLASS in characterizing the Milky Way's emission, a crucial step in refining analyses of the cosmic microwave background.

Journal Information: The Astrophysical Journal (2024). DOI: 10.3847/1538-4357/ad1abf