Scientists at the University of Missouri have identified a small group of unusual objects in the early universe. Using NASA's James Webb Space Telescope (JWST), Haojing Yan and his team at Mizzou's College of Arts and Science spotted these strange objects, which seem like one galactic thing but have the unmistakable fingerprints of something else entirely.
These objects have "point-like" features that would normally place them in one of two categories: stars or quasars, which are the brilliant cores of distant galaxies powered by supermassive black holes. But when researchers analyzed their light using spectroscopy, they found no broad emission lines — only narrow ones, a telltale sign of active star formation typically seen in galaxies.
Because these objects mix characteristics that don't usually go together, the researchers nicknamed them "platypus galaxies" after the animal with a mishmash of parts.
"Each property on its own is familiar to us," Haojing Yan, a Mizzou astronomy professor and co-author of the study, said. "But when added together, they create something we've never seen before."
A closer look
The discovery comes as scientists continue to examine JWST's deep-space images, which allow them to see the universe as it appeared billions of years ago, and raises new questions about how galaxies were created.
"Our ongoing theory states that galaxies were formed by merging with other galaxies, often through violent collisions," Yan said. "But these 'platypus galaxies' may have formed quietly, without such dramatic events. This suggests the early universe may have been more flexible and creative than we thought."
While the evidence is not yet strong enough to overturn existing theories, researchers believe the signs are strong enough to suggest some galaxies may have formed in ways previously unaccounted for.
While more research is needed, the team plans to gather additional data on hundreds of other cosmic objects to see if they also share these unusual traits. This means collecting spectroscopy data on each — essentially breaking their light into a rainbow and reading it like a barcode. This technique reveals details such as the age and chemical makeup of galaxies and how their stars are formed.
"If these objects are really a new type of galaxy, it tells us we've been missing part of the story," said Bangzheng "Tom" Sun, a graduate student in Yan's lab and co-author of the study. "And we're just beginning to uncover it."
The study, "A new population of point-like, narrow-line objects revealed by the James Webb Space Telescope," was presented at the 247th meeting of the American Astronomical Society. Mizzou undergraduate student Riley Shive is also a co-author on the study.
