Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have detected oxygen in the most distant confirmed galaxy ever found, JADES-GS-z14-0. This detection, made by two different teams, suggests the galaxy is much more chemically mature than expected.
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This is an artist’s impression of JADES-GS-z14-0. Image credit: ESO / M. Kornmesser.
Discovered in 2024, JADES-GS-z14-0 (GS-z14 for short) is so far away, its light took 13.4 billion years to reach us, meaning we see it as it was when the Universe was less than 300 million years old — about 2% of its present age.
“It is like finding an adolescent where you would only expect babies,” said Sander Schouws, a Ph.D. candidate at Leiden Observatory and first author of a paper accepted for publication in the Astrophysical Journal.
“The results show the galaxy has formed very rapidly and is also maturing rapidly, adding to a growing body of evidence that the formation of galaxies happens much faster than was expected.”
Galaxies usually start their lives full of young stars, which are made mostly of light elements like hydrogen and helium.
As stars evolve, they create heavier elements like oxygen, which get dispersed through their host galaxy after they explode in supernova events.
Researchers had thought that, at 300 million years old, the Universe was still too young to have galaxies ripe with heavy elements.
However, the two ALMA studies indicate GS-z14 has about 10 times more heavy elements than expected.
The inset in this image shows JADES-GS-z14-0 as seen with ALMA; the two spectra result from independent analysis of ALMA data by two teams of astronomers; both found an emission line of oxygen, making this the most distant detection of oxygen, when the Universe was only 300 million years old. Image credit: ALMA / ESO / NAOJ / NRAO / Carniani et al. / Schouws et al. / NASA / ESA / CSA / Webb / STScI / Brant Robertson, UC Santa Cruz / Ben Johnson, CfA / Sandro Tacchella, Cambridge / Phill Cargile, CfA.
“I was astonished by the unexpected results because they opened a new view on the first phases of galaxy evolution,” said Dr. Stefano Carniani, an astronomer at the Scuola Normale Superiore of Pisa and lead author of a paper published in the journal Astronomy & Astrophysics.
“The evidence that a galaxy is already mature in the infant Universe raises questions about when and how galaxies formed.”
The oxygen detection has also allowed astronomers to make their distance measurements GS-z14 much more accurate.
“The ALMA detection offers an extraordinarily precise measurement of the galaxy’s distance down to an uncertainty of just 0.005%,” said Eleonora Parlanti, a Ph.D. student at the Scuola Normale Superiore of Pisa.
“This level of precision — analogous to being accurate within 5 cm over a distance of 1 km — helps refine our understanding of distant galaxy properties.”
“While the galaxy was originally discovered with the NASA/ESA/CSA James Webb Space Telescope, it took ALMA to confirm and precisely determine its enormous distance,” said Dr. Rychard Bouwens, an astronomer at Leiden Observatory.
“This shows the amazing synergy between ALMA and Webb to reveal the formation and evolution of the first galaxies.”
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Sander Schouws et al. 2025. Detection of [OIII]88μm in JADES-GS-z14-0 at z=14.1793. ApJ, in press; arXiv: 2409.20549
Stefano Carniani et al. 2025. The eventful life of a luminous galaxy at z=14: metal enrichment, feedback, and low gas fraction? A&A, in press; doi: 10.1051/0004-6361/202452451
