University of Arizona astronomers have discovered surprising details about a galaxy that existed less than 300 million years ago when the universe was just 2% of its current age. Using NASA's James Webb Space Telescope, they found that JADES-GS-z14-0 is much brighter and chemically more complex than expected, challenging current understanding of early galaxy formation. The discovery of large amounts of oxygen suggests that the galaxy formed stars at least 100 million years ago, pushing back the timeline of cosmic evolution.

This infrared image from NASA's James Webb Space Telescope was captured by the onboard near-infrared camera of the James Webb Space Telescope's Advanced Deep Space Extragalactic Survey (JADES) project. NIRCam data are used to determine which galaxies require further study through spectroscopic observations. The redshift of one of the galaxies, JADES-GS-z14-0 (shown here), was determined to be 14.3, making it the current record holder for the most distant known galaxy. This corresponds to less than 300 million years after the Big Bang. Image credits: NASA, European Space Agency, Canadian Space Agency, STScI, Brandt Robertson (UC Santa Cruz), Ben Johnson (CfA), Sandro Tacera (University of Cambridge), Phil Cargill (CfA)

University of Arizona astronomers have discovered new details about a very mature galaxy that existed when the universe was less than 300 million years old and was only 2% of its current age.

Researchers used NASA's James Webb Space Telescope (JWST) to study the galaxy, known as JADES-GS-z14-0, and found that it is unexpectedly bright and chemically complex for such an early time in the history of the universe. The discovery provides a rare window into the formation of the universe.

The study, published in the journal Nature Astronomy, builds on a 2024 discovery that identified JADES-GS-z14-0 as the most distant galaxy ever observed. While the initial discovery established its extreme distance and astonishing brightness, new research explores its chemical composition and evolutionary state in greater depth.

The research is part of the James Webb Space Telescope's Advanced Deep Extragalactic Survey (JADES), a large-scale project designed to detect distant galaxies.

It wasn't just a chance discovery of something unexpected, said study co-author Kevin Heinlein, a research associate at the University of Arizona's Steward Observatory. The survey was designed specifically to find distant galaxies, but this galaxy broke the team's record in a way they didn't expect; it was inherently bright and chemically complex, which was completely unexpected so early in the history of the universe.

"It's not just a tiny lump. It's bright and quite broad for the age of the universe we observe," Heinlein said.

Timeline of the Universe: While we're not sure when the first stars began to shine, we do know that they must have formed sometime after the Recombination Era, when hydrogen and helium atoms were formed (380,000 years after the Big Bang), and before the oldest known galaxies existed (400 million years after the Big Bang). The ultraviolet light emitted by the first stars split the neutral hydrogen gas filling the universe into hydrogen ions and free electrons, ushering in the era of reionization and ending the Dark Ages of the universe. Image source: NASA, ESA, CSA, STScI

"We found this galaxy in a small area of ​​the sky, which means there should be many more galaxies like this out there," said Jacob Helton, lead author of the study and a graduate student at Stewart Observatory. "If we looked at the entire sky, which the James Webb Space Telescope cannot do, we would end up discovering more of these extreme objects."

The research team used a variety of instruments on the James Webb Space Telescope, including the Near Infrared Camera (NIRCam), the construction of which was led by University of Alberta astronomy professor Marcia Rieke. Another instrument on the telescope, the Mid-Infrared Instrument (MIRI), revealed something unusual: large amounts of oxygen.

In astronomy, anything heavier than helium is considered a "metal," Helton said. This metal requires generations of stars to produce. The early universe contained only hydrogen, helium and trace amounts of lithium. But the discovery of large amounts of oxygen in the JADES-GS-z14-0 galaxy suggests that the galaxy may have been forming stars for 100 million years before it was observed.

In order to produce oxygen, a galaxy must have started very early because it would have to form a generation of stars, said George Rieck, professor of astronomy and senior author of the study. These stars must evolve and explode as supernovae, releasing oxygen into interstellar space from which new stars will form and evolve.

"It takes a very complex cycle to get that much oxygen in this galaxy. So, it's really mind-boggling," Rick said. The discovery suggests stars formed earlier than scientists previously thought, delaying the formation of the first galaxies after the Big Bang.

The observation required approximately nine days of telescope time, including 167 hours of NIRCam imaging and 43 hours of MIRI imaging, focusing on a very small part of the sky.

University of Alberta astronomers were lucky that the galaxy happened to be in the sweet spot for their MIRI observations. If they had pointed the telescope in any direction, even just a fraction of a degree, Helton said, they would have missed this crucial mid-infrared data.

"Imagine a grain of sand at the end of your arm. You see how big it is in the sky — that's how big we see it," Helton said.

The existence of such well-developed galaxies so early in the history of the universe provides a powerful test case for theoretical models of galaxy formation.

"We were involved because the University of Alberta has been at the forefront of infrared astronomy since the mid-1960s when it was just getting started. We had the first major infrared astronomy group at the Lunar and Planetary Laboratory, with members including Gerard Kuiper, Frank Low and Harold Johnson," said Rieke.

As humans gain the ability to directly observe and understand the galaxies that existed in the early days of the universe, it could provide key insights into how the universe evolved from simple elements to the complex chemistry necessary for life as we know it.

"We are in an incredible time in the history of astronomy," Heinlein said. "We're able to look at galaxies well beyond the scope of human discovery and look at them in so many different ways and really understand them. It's really amazing."

Compiled from /ScitechDaily