It hasn't been long since the James Webb Space Telescope began operating, but the data collected since then continues to set new records. Recently, researchers reported a unique discovery – Webb's keen eye discovered several of the oldest galaxies in the Universe. Note that the titles of «oldest» galaxies have been awarded to a variety of objects as their discovery occurs gradually, but the galaxies discovered by Webb pose a serious problem for astronomers – all because they destroy existing models of the formation of these inhabitants of the cosmos. Thus, the most distant galaxy, JADES-GS-z14-0, is visible in the images as it was about 300 million years after the Big Bang (existing at least 100 million years earlier than the previous record holder). This means that the light that Webb captured took approximately 13.5 billion years to reach us. The neighboring galaxy is almost the same distance
and ranks second in the ranking of the most ancient galaxies.
The James Webb Telescope has seen the most ancient galaxies in the Universe. Image: cdn.mos.cms.futurecdn.net
Contents
- 1 Record-breaking galaxy
- 2 Why are ancient galaxies so bright?
- 3 Redshift
- 4 Surprise from space
Record-breaking galaxy
The announcement of the discoveries, made in October 2023 and January 2024, is the latest advance in the ongoing exploration of the birth of the universe, which the $10 billion telescope has facilitated as part of the JWST Advanced Deep Extragalactic Survey (JADES) program. JADES aims to provide vital insight into how stars, gas and black holes evolved in primordial galaxies shortly after the birth of the universe 13.8 billion years ago.
These galaxies join a small but growing population of galaxies in the first half-billion years of cosmic history, thanks to which we can study stellar populations and the characteristic structures of the chemical elements in them, says study co-author Francesco D'Eugenio of the Kavli Institute of Cosmology.< /p>
The JADES-GS-z14-0 galaxy observed by Webb is currently the most distant and earliest object ever discovered. Researchers note that it appeared just 300 million years after the Big Bang.
The image taken by the James Webb Space Telescope shows the oldest galaxy ever discovered. Image: NASA/ESA/CSA/STSc/B. Robertson (UC Santa Cruz)/B. Johnson (CfA)/S. Tacchella (Cambridge)/P. Cargile (CfA)
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However, JADES-GS-z14-0 is notable not only for its distance from Earth and its age. With a width of about 1600 light years, this space object differs from others in its size and brightness. So, according to astrophysicists, the size of JADES-GS-z14-0 proves that most of the light comes from a large number of young stars, and not from matter falling into the supermassive black hole at the center of the galaxy, which is why it could seem much smaller».
Why are ancient galaxies so bright?
The extreme brightness of JADES-GS-z14-0 and the fact that this brightness is provided by young stars means that JADES-GS-z14-0 represents the most striking evidence yet for the rapid formation of large massive galaxies in the early Universe .
JADES team member and UC Santa Cruz researcher Ben Johnson notes that Webb's discovery shows that galaxy formation in the early Universe was very rapid and intense.
The James Webb Space Telescope sees early galaxies in red. This is what the oldest galaxy in the Universe, JADES-GSz14-0, looks like. Image: NASA/ESA/CSA/STSc/B. Robertson (UC Santa Cruz)/B. Johnson (CfA)/S. Tacchella (Cambridge)/P. Cargile (CfA)
The amazing thing is that in the future, the James Webb Space Telescope will allow us to discover more such galaxies, perhaps when the Universe was even younger. And this, in turn, is an excellent opportunity to study the origin and evolution of galaxies, scientists say in a statement.
Recall that the James Webb Telescope is an expert in observing early galaxies thanks to the high infrared sensitivity of its instruments, in particular its main imaging device, the near-infrared camera (NIRCam). So, in 2023, Webb discovered hypothetical stars that feed on dark matter.
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The light emanating from these galaxies at the dawn of the space age has a wide range of wavelengths, similar to light from galaxies closer to the Milky Way. A journey lasting billions of years converts this light into low-energy, long-wavelength radiation in the near and infrared regions of the electromagnetic spectrum.
A diagram showing the electromagnetic spectrum and its associated wavelength of light. The sun emits light across the entire electromagnetic spectrum, including all colors of visible light. (Image courtesy of NASA's Imagine the Universe program)
The very fabric of space expands, and when light passes through it, its wavelength increases along with it. «This causes the light to «shift» to the red part of the electromagnetic spectrum, hence the name of this phenomenon – «red shift»», astronomers explain.
Red shift
As we told earlier , more distant galaxies have to cross more space (which stretches as they expand) before their light reaches us, which is why redshift occurs.
It is what researchers use to measure the distance to celestial objects with a known spectrum. And because light takes a certain amount of time to reach an object, this distance can be used to calculate how long ago these galaxies existed as we see them.
The graph shows a red line going down from left to right: «this galaxy was formed 300 million years after the Big Bang». (Image credit: NASA, ESA, CSA, J. Olmsted (STScI). Science: S. Carniani (High School of Natural Sciences), JADES collaboration.)
When both ancient galaxies were first discovered by Webb, scientists theorized that they could be heavenly neighbors. This idea, however, was dispelled last October when the JADES team conducted an in-depth analysis of JADES-GS-z14-0 using NIRCam over five days. The use of filters specifically designed to identify early galaxies confirmed the extreme distance to JADES-GS-z14-0.
We simply could not find any plausible explanation for the fact that this galaxy is simply a neighbor of a closer galaxy,” said Kevin Hainlein, a member of the JADES team at the University of Arizona.
The galaxy also surprised its discoverers in that that its emission is redder than expected. The problem turned out to be that the light from the JADES-GS-z14-0 «turns red» because of the dust it contains, which will become the building blocks for stars that will help this galaxy grow even larger.
Surprise from space
Another surprise was the discovery of oxygen in JADES-GS-z14-0. Recall that elements heavier than hydrogen and helium are formed by stars during their lives and then distributed throughout galaxies when those stars explode. The presence of oxygen in JADES-GS-z14-0 may indicate that at leastone generation of stars has already lived and died in this very ancient galaxy.
“Taken together, these observations suggest that JADES-GS-z14-0 is not like the types of galaxies predicted by theoretical models and computer simulations in the very early Universe,” says Jake Helton of the observatory. Steward and the University of Arizona.
In the future we will discover even more ancient galaxies. Image: static.scientificamerican.com
Given the observed brightness of a source, we can predict how it might increase over cosmic time, and so far we have not found suitable analogues among the hundreds of other galaxies we observed at high redshift in our study, he added.
Given the relatively small area of sky that the Webb Space Telescope examined to find JADES-GS-z14-0, the new discovery has major implications for the predicted number of bright galaxies we see in the early Universe .
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So it's likely that over the next decade, with Webb's help, astronomers will discover many such luminous galaxies, perhaps even more ancient. You can read the full text of articles about this amazing new discovery on the arXiv preprint server. Articles that simultaneously study the properties of galaxy light can be found here and here.