Research conducted by the Atacama Cosmology Telescope (ACT) collaboration has yielded images that provide an unprecedented view of the universe's infancy. These images capture the cosmic microwave background (CMB) radiation, visible 380,000 years after the Big Bang. The research was conducted by an international team, including astrophysicist Neelima Sehgal from Stony Brook University.
The new images reveal light that traveled over 13 billion years to reach the ACT in Chile. They offer insights into the universe when it was approximately 380,000 years old. Suzanne Staggs, Director of ACT and a professor at Princeton University, commented on the significance: "We are seeing the first steps towards making the earliest stars and galaxies."
These findings confirm a simple model of the universe and rule out many competing alternatives. The results will be presented at the American Physical Society Annual Meeting on March 19.
Neelima Sehgal noted that these images surpass previous CMB observations in sensitivity and resolution. She emphasized, "With these images, we have achieved a sensitivity over half the sky that surpasses previous 'baby pictures' of the universe." The polarization data from ACT offers new insights into early cosmic movements.
Jo Dunkley, another researcher involved in analyzing ACT data, remarked on how this work helps piece together the story of how our universe evolved: "By looking back to that time...we can piece together the story of how our universe evolved."
ACT's new measurements refine estimates for both the age of the universe and its expansion rate today. The data confirm a lower value for the Hubble constant than other measurements suggest.
The Stony Brook team has been engaged in CMB analysis for over a decade under Sehgal's leadership. Observations by ACT concluded in 2022, with future attention shifting to Simons Observatory at the same location.
Sehgal's research is funded by various institutions including NSF and DOE. The ACT project also received support from Princeton University, University of Pennsylvania, and Canada Foundation for Innovation award among others.