Two different teams of astronomers have detected oxygen in the most distant known galaxy, JADES-GS-z14-0. This record-breaking detection is making astronomers rethink how quickly galaxies formed in the early Universe.
“It is a fantastic discovery, exploring the very limits of the ALMA (Atacama Large Millimeter Array) and James Webb Space telescopes. This galaxy is very bright and very far, and as a consequence, I think this one galaxy will form the basis of our new understanding of the earliest beginnings of galaxy formation”, says Tom Bakx, post doctoral researcher at Chalmers and part of one of the two research teams.
Discovered by the James Webb Space Telescope last year, JADES-GS-z14-0 is the most distant confirmed galaxy ever found: it 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. The new oxygen detection with ALMA, a telescope array in Chile's Atacama Desert,suggests the galaxy is much more chemically mature than 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 die. 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 that JADES-GS-z14-0 has about 10 times more heavy elements than expected. 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.
“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”, says Stefano Carniani, of the Scuola Normale Superiore of Pisa, Italy, and lead author on the paper "The eventful life of a luminous galaxy at z=14", published in Astronomy & Astrophysics.
The oxygen detection has also allowed astronomers to make their distance measurements to JADES-GS-z14-0 much more accurate. This shows the amazing synergy between ALMA and JWST to reveal the formation and evolution of the first galaxies. But there is even more intriguing things about the galaxy, for instance the presence of cosmic dust.
“I’m very interested in this aspect of it, especially since we’re also seeing bright emission lines that indicate the ingredients for dust are likely available throughout the galaxy. We’re now working to test the formation mechanisms. Collaborating with chemists at Chalmers, we are using this galaxy in particular as a test-bed”, says Tom Bakx, Chalmers.
More info:
Read more about the discoveries and see high resolution images in the European Southern Observatory press release: Oxygen discovered in most distant known galaxy.
You can also learn more in an episode of the European Southern Observatory's Youtube series Chasing Starlight, you can learn more about everything behind this incredible achievement, and also how it's changing what we knew about the conditions of the early Universe.
On spectra and emission lines:
In astronomy, spectra and emission lines are referring to the light that an object in space emits at specific wavelengths. By splitting the light into a spectrum – like a rainbow created by a prism – scientists can see distinct "lines" that reveal the presence of different elements. Each element, like oxygen, has its own unique pattern of emission lines, allowing researchers to identify it even billions of light-years away. Read more about emission lines on the Nasa website
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