Webb Telescope: Monster Star Clumps in Galactic Wreckage
Uncover the secrets of the early universe with the James Webb Space Telescope! Astronomers are leveraging the Webb Telescope’s advanced infrared capabilities to study luminous infrared galaxies (LIRGs), which are essentially cosmic star factories undergoing mergers. These galactic collisions trigger intense star formation, creating “monster star clumps” far more massive than those in our Milky Way. News Directory 3 explores how these observations illuminate galaxy evolution, offering a glimpse into the formation of the early universe. We delve into the impact of these mergers and the critical role the JWST plays in revealing these otherwise obscured features. Find out more about the future of our galaxy. Discover what’s next in this captivating field.
Star Factories Reveal Secrets of Early Universe, Galaxy Evolution
Updated June 14, 2025
Astronomers are studying distant, massive star factories in galaxies across the local universe, offering a glimpse into the processes that shaped galaxies in the early universe. These findings may even shed light on the future of the Milky way.
These galaxies, known as luminous infrared galaxies (LIRGs) and ultra-luminous infrared galaxies (ULIRGs), are relatively rare. Sean Linden, a research associate at the University of Arizona Steward Observatory, said that only 202 are known within 1.3 billion light-years of Earth. He presented the findings at the 246th meeting of the American Astronomical Society on June 11.
Unlike spiral galaxies such as the Milky Way, lirgs and ULIRGs are in the process of merging.These galaxies often display features such as two galactic nuclei or extended “tails” caused by gravitational forces. They also contain dense regions of newborn stars, called “clumps,” which are far more massive than those found in evolved galaxies not undergoing mergers. These star-forming clumps are key to understanding galaxy evolution.
“these galaxies are very clumpy, very different from the beautiful spiral galaxies that we see now, such as the Milky Way,” Linden said. “And we certainly know from cosmological simulations that these clumps were the building blocks of galaxies in the early universe.”
The great Observatories All-sky LIRG Survey (GOALS) combines data from NASA’s Spitzer, Hubble, Chandra, and GALEX space observatories to study more than 200 of the most luminous infrared galaxies. Observations from the James Webb Space Telescope (JWST) have provided the most complete census of these galaxies to date. The survey ran from October 2023 to september 2024, and the team plans to publish the results in The Astrophysical Journal.
“You can imagine a million suns forming in one small, compact region, and within one of those galaxies, there are hundreds of thousands of such clumps,” Linden said.
By comparison, the most massive young clumps in the Milky Way have masses of about 1,000 suns, with an average of one star born each year.
Linden explained that when galaxies merge, star formation rates increase dramatically, leading to the formation of massive clumps not seen in other galaxies. The infrared capabilities of JWST have allowed astronomers to see through the dust that previously obscured these features.
The survey results confirm that disk-like galaxies contain fewer star formation clumps, with most star formation occurring in small clumps, as seen in the Milky Way.Mergers produce bigger clumps, and more star formation takes place within them.
“We’re now finding these massive clumps in the local universe,” Linden said.”We are beginning to complete the picture by comparing for the first time observations of massive clumps from both the nearby and the distant universe.”
Linden, who focused on imaging the clumps and star clusters and led the data acquisition, reduction, and analysis, said that studying these star-forming clumps helps researchers understand how galaxies evolved over time.
“In a sense, you look at the local universe, and it gives you details about what would have happened 10 billion years ago,” Linden said.
He added that the early universe was denser, with more frequent galaxy mergers, producing massive star-forming clumps.As the universe expanded, galaxies became more like the Milky Way.
“The universe used to be much more violent and extreme in the past, and it’s now settling down,” Linden said.
What’s next
Linden said that the surveyed galaxies also offer hints about the future. The Milky Way and Andromeda galaxies are expected to collide in several billion years, which could trigger another round of massive star formation.