Missouri University scientists using the James Webb Space Telescope to hunt for ancient galaxy candidates that may have formed in the early phases of the universe have spotted 300 “mysterious objects,” which they say are too bright to fit into traditional early galaxy formation models.
If planned follow-up spectroscopy studies confirm that these mystery objects spotted by JWST’s ultrasensitive infrared cameras are ancient galaxies that are brighter than expected, the research team behind the discovery believes their findings could prompt scientists to revise existing theories of early galaxy formation to accommodate these brighter examples.
“These mysterious objects are candidate galaxies in the early universe, meaning they could be very early galaxies,” explained Haojing Yan, an astronomy professor in Mizzou’s College of Arts and Science and co-author on the study detailing the team’s discovery. “If even a few of these objects turn out to be what we think they are, our discovery could challenge current ideas about how galaxies formed in the early universe — the period when the first stars and galaxies began to take shape.”
Mysterious Objects Spotted by James Webb Due to Redshift ‘Dropout’
For astronomers interested in stars, galaxies, and other objects formed during the first billion years after the Big Bang, the instruments aboard the JWST have proven invaluable. Specifically, the observatory’s Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument are designed to detect infrared light. Because light wavelengths stretch out as they travel across the vastness of space, researchers search for extremely long infrared light that could have traveled that intergalactic distance.
“This stretching is called redshift, and it helps us figure out how far away these galaxies are,” Yan explained. “The higher the redshift, the farther away the galaxy is from us on Earth, and the closer it is to the beginning of the universe.”
To increase the odds that the infrared light detected by JWST was from these distant early galaxy candidates, the research team employed the “dropout technique.” According to Bangzheng “Tom” Sun, a Ph.D. student working with Yan and the lead author of the study, the dropout technique looks for infrared signatures that “vanish” in bluer spectra. Sun noted that this disappearing signal is a sign that the observed infrared light “has traveled across vast distances and time.”
“This phenomenon is indicative of the ‘Lyman Break,’ a spectral feature caused by the absorption of ultraviolet light by neutral hydrogen,” the researcher explained. “As redshift increases, this signature shifts to redder wavelengths.”
Spectroscopy Analysis of “Very” High Redshifts Should Resolve Mystery
Although the initial analysis of the very bright objects spotted by JWST suggests they could be ancient galaxies, the team notes that objects this massive, formed this early in the universe, should not be this bright. Yan notes that the best way to resolve the dispute, which involves determining if the 300 objects are “very” high redshifts, wasn’t immediately available.
“Ideally, this would be done using spectroscopy, a technique that spreads light across different wavelengths to identify signatures that would allow an accurate redshift determination,” he said.
In lieu of full spectroscopic data, the team used an alternate technique called spectral energy distribution fitting. According to the statement, this approach provided the team with a “baseline” for estimating the redshift of their galaxy candidates, “along with other properties such as age and mass,” which supported the galaxy hypothesis.
The team said the final test of their hypothesis will come when full spectroscopy of the objects is available for study. Designed to split light into its wavelengths like a prism, the team said the technique will “reveal a galaxy’s unique fingerprint,” which can reveal the galaxy’s age, composition, and formation method. According to Sun, spectroscopy has already offered support that one of the objects is an early galaxy, but “this object alone is not enough.”
“We will need to make additional confirmations to say for certain whether current theories are being challenged,” he said.
Still, Yan added, even if only a few of the mysterious objects are confirmed to originate from the early universe, “they will force us to modify the existing theories of galaxy formation.”
The study, “On the very bright dropouts selected using the James Webb Space Telescope NIRCam instrument,” was published in The Astrophysical Journal.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.