Oxygen discovered in most distant known galaxy

Credit: ALMA (ESO/NAOJ/NRAO)/S. Carniani et al./S. Schouws et al/JWST: NASA, ESA, CSA, STScI, Brant Robertson (UC Santa Cruz), Ben Johnson (CfA), Sandro Tacchella (Cambridge), Phill Cargile (CfA)

The farthest known galaxy, JADES-GS-z14-0, has been found to contain oxygen by two distinct groups of scientists.  The European Southern Observatory (ESO) is a partner in the Atacama Large Millimeter/submillimeter Array (ALMA), which enabled the finding, which was documented in two different studies.  Astronomers are reconsidering how quickly galaxies formed in the early cosmos in light of this unprecedented discovery.

 The most distant verified galaxy ever discovered, JADES-GS-z14-0, was discovered last year. Because of its great distance, it took 13.4 billion years for its light to reach us, allowing us to view it as the universe was less than 300 million years old, or roughly 2% of its current age.

The galaxy may be far more chemically mature than previously thought, according to the new oxygen observation made with ALMA, a telescope array in Chile's Atacama Desert.

Sander Schouws, a Ph.D. candidate at Leiden Observatory in the Netherlands and the first author of the Dutch-led study that was accepted for publication in The Astrophysical Journal, compares it to finding an adolescent where you would only anticipate babies.

"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."

Young stars, which are primarily composed of light elements like hydrogen and helium, are typically the first stars to form in galaxies.  After they die, heavier elements like oxygen, which are produced by evolving stars, are released into their host galaxy.

 At 300 million years ago, scientists believed the universe was still too young to contain galaxies that were rich in heavy metals.  But according to the two ALMA studies, JADES-GS-z14-0 has around ten times as many heavy elements as anticipated.

The primary author of the work accepted for publication in Astronomy & Astrophysics, Stefano Carniani of the Scuola Normale Superiore of Pisa, Italy, says, "I was astonished by the unexpected results because they opened a new view on the first phases of galaxy evolution."  "The evidence that a galaxy is already mature in the infant universe raises questions about when and how galaxies formed."

 Additionally, the oxygen detection has greatly improved the accuracy of astronomers' distance measurements to JADES-GS-z14-0.

With an error of only 0.005%, the ALMA finding provides an incredibly accurate determination of the galaxy's distance.  Eleonora Parlanti, an author and Ph.D. candidate at the Scuola Normale Superiore of Pisa, adds, "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."

 Associate Professor Rychard Bouwens, who is part of the team at Leiden Observatory, adds, "Although the galaxy was first discovered with the James Webb Space Telescope, it took ALMA to confirm and precisely determine its enormous distance."

 "This shows the amazing synergy between ALMA and JWST to reveal the formation and evolution of the first galaxies."

According to Gergö Popping, an ESO astronomer at the European ALMA Regional Center who did not participate in the research, "This obvious oxygen finding in JADES-GS-z14-0 truly caught me off guard.  It implies that galaxies can develop more quickly than previously believed following the Big Bang.

 "This result showcases the important role ALMA plays in unraveling the conditions under which the first galaxies in our universe formed."

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