Galaxies surged in size during early universe growth phase

Galaxies surged in size during early universe growth phase
by Clarence Oxford
Los Angeles CA (SPX) Apr 24, 2025
A new astronomical survey led by the University of Kansas using the James Webb Space Telescope (JWST) has delivered fresh insight into galaxy evolution during the universe's peak star-forming era known as "cosmic noon," which occurred roughly 2 to 3 billion years after the Big Bang.

The MIRI EGS Galaxy and AGN (MEGA) survey reveals that half of all the stars in today's galaxies were born during this dynamic period. The research highlights the twin engines of galactic evolution at play-bursts of star formation and the dramatic expansion of central black holes.

The KU team invites the public to join their classification efforts through the Cosmic Collisions Zooniverse project, which asks volunteers to help identify galaxy shapes and mergers. "Our aim is to conduct the most extensive JWST mid-infrared survey to date," said principal investigator Allison Kirkpatrick, associate professor of physics and astronomy at KU. "The mid-infrared reveals what's hidden by dust, allowing us to understand the pace of star formation and black hole growth in obscured galaxies."

Using JWST's advanced mid-infrared capabilities, the team examined galaxies located in the Extended Groth Strip-a galaxy-dense observational window near the Ursa Major constellation. Light from these distant galaxies began its journey during cosmic noon, allowing researchers to reconstruct galactic activity from 10 billion years ago.

"The Extended Groth Strip is now one of the premier JWST fields," said Kirkpatrick. "I was part of the CEERS proposal, which received the telescope's first data. Within this narrow sky patch, about the size of the Moon, we can detect some 10,000 galaxies."

Lead author Bren Backhaus, a KU postdoctoral researcher, transformed JWST's raw data into calibrated, aligned, and science-ready images. "Each filter captures light differently, much like red, green, or blue channels in photography. But image misalignments, dead pixels, and known artifacts had to be corrected first," she explained. Her final task was photometric analysis-measuring and cataloging the light each galaxy emitted through various filters.

"It was my first experience working with photometry data, and it was rewarding to catalog galaxies and see cosmic structures no one else had," Backhaus said.

To date, the KU team has used 67 hours of JWST observation time and secured funding for an additional 30 hours. Until the data is made public in raw form, it remains available exclusively to KU researchers for analysis and training.

"This is the most JWST data ever brought to KU under the leadership of a local principal investigator," Kirkpatrick noted. "Students here are analyzing galaxies that may be precursors to the Milky Way, observing how they form stars and expand their central black holes, and examining how mergers alter their structure."

She emphasized that MEGA offers a singular chance for KU students and scientists to explore galactic history during one of the universe's most formative phases. "Every one of my students is contributing to this groundbreaking work."

Research Report:MEGA Mass Assembly with JWST: The MIRI EGS Galaxy and AGN Survey