Suffolk Reporter

Research conducted by the Atacama Cosmology Telescope (ACT) collaboration has resulted in the clearest images yet of the universe's early stages. These images capture the cosmic microwave background (CMB) radiation, visible 380,000 years after the Big Bang.

The international team includes astrophysicist Neelima Sehgal and her group from Stony Brook University. They have been pivotal in analyzing this afterglow light from the Big Bang. The new images reveal a universe at about 380,000 years old, akin to baby pictures of a now middle-aged cosmos.

Suzanne Staggs, director of ACT and professor at Princeton University, stated: “We are seeing the first steps towards making the earliest stars and galaxies.” She emphasized that ACT's ability to view light polarization distinguishes it from earlier telescopes like Planck.

The findings confirm a simple model of the universe while dismissing most competing theories. These results will be presented at the American Physical Society Annual Meeting on March 19.

In its infancy, the universe was opaque due to hot primordial plasma. The CMB represents a stage when light could finally propagate freely. The new images offer a clear view of subtle variations in gas density and velocity and detail hydrogen and helium movement during cosmic infancy.

“With these images, we have achieved a sensitivity over half the sky that surpasses previous ‘baby pictures’ of the universe,” said Sehgal. She noted that their work supports the Standard Model of Cosmology without finding discrepancies.

Jo Dunkley from Princeton University remarked: “By looking back to that time...we can piece together how our universe evolved.”

ACT's measurements have refined estimates for both the age of the universe and its current expansion rate. They confirmed a lower Hubble constant value with increased precision compared to other methods.

The Stony Brook team has been involved in CMB analysis for over ten years under Sehgal’s leadership. The research is supported by various institutions including NSF awards and involves collaborators from 65 institutions globally.

With ACT observations completed in 2022, focus shifts to the Simons Observatory in Chile where Stony Brook is an institutional partner. The new data is publicly available on NASA’s LAMBDA archive with articles accessible on arXiv.org.

Sehgal’s research received funding from U.S. agencies such as NSF and DOE, with additional support for ACT provided by Princeton University, University of Pennsylvania, among others.