The James Webb Space Telescope detects the first two galaxies ever seen (image)

The James Webb Space Telescope (JWST) has discovered not one but two of the first and most distant galaxies ever seen, continuing to break the records it previously set.

The most distant galaxy, JADES-GS-z14-0, is seen as it was about 300 million years after big Bang, existing at least 100 million years before the previous record holder. This means that the light JWST What we have seen of this primordial galaxy has traveled 13.5 billion years on its way to reach us.

JADES-GS-z14-0 is not alone either. It was discovered together with another galaxy, JADES-GS-z14-1, which is almost as distant and ranks second in the ranking of the first galaxies ever seen by humanity.

Related: James Webb Space Telescope detects three of our universe’s first galaxies

The announcement of the findings, made in October 2023 and January 2024, are the latest developments in the ongoing investigation of cosmic dawn which the $10 billion telescope facilitated as part of the JWST Advanced Deep Extragalactic Survey (JADES) program. JADES aims to provide vital information about how stars, gas and black holes evolved in early galaxies when the 13.8 billion-year-old universe was very young.

“These galaxies join a small but growing population of galaxies from the first half billion years of cosmic history, where we can really probe the stellar populations and the distinct patterns of chemical elements within them,” said team member Francesco D’ and scientist at the Kavli Institute of Cosmology. Eugene said in a statement.

However, JADES-GS-z14-0 is not only notable for how far it is from Earth and how early it existed in the cosmos. With a width of about 1,600 light years, this “cosmic dawn” galaxy it is also notable for being large and bright.

“The size of the galaxy clearly proves that most of the light is produced by large numbers of young stars, rather than material falling onto a galaxy. supermassive black hole at the center of the galaxy, what would be [make it] appear much smaller,” said JADES team leader Daniel Eisenstein of Harvard & Smithsonian’s Center for Astrophysics (CfA). said in a separate statement.

The extreme brightness of JADES-GS-z14-0 and the fact that this luminosity is powered by young stars means that this galaxy represents the most impressive evidence for the rapid formation of large, massive galaxies in the early Universe found so far.

JADES team member and University of California-Santa Cruz researcher Ben Johnson added that JADES-GS-z14-0 shows that galaxy formation in the early universe was very rapid and intense.

“JWST will allow us to find more of these galaxies, perhaps when the universe was even younger,” he said. “It’s a wonderful opportunity to study how galaxies began.”

The James Webb Space Telescope sees red to detect early galaxies

JWST is adept at observing early galaxies thanks to the high infrared sensitivity of its instruments, particularly its primary imager, the Near Infrared Camera (NIRCam).

The light leaves these dawn cosmic galaxies with a wide range of wavelengths similar to the light from galaxies closer to the Milky Way. It is the billion-year journey that transforms this light into low-energy, long-wavelength light in the near-infrared and infrared regions of the electromagnetic spectrum.

The very fabric of space is expanding, and as light passes through it, its wavelength is stretched along with it. This causes the light to “shift” toward the red end of the electromagnetic spectrum, hence the name of this phenomenon, “redshift.”

Galaxies that are more distant have to pass through more space (which is stretched as they expand) before their light reaches us, and therefore that light is redshifted more. Redshift, denoted as z, can therefore be used to measure the distance to celestial objects with a known spectrum. And since light takes a finite time to travel, this distance can be used to calculate how long ago these galaxies existed as we see them.

JADES-GS-z14-0 has a redshift of z = 2:32 p.m., while the most distant previous galaxy, JADES-GS-z13-0, has a redshift of z = 13.2, which placed it as existing 400 million years after the Big Bang. Clearly, this newly discovered galaxy has absolutely broken that record, with the JWST going back in time for another 100 million years or so.

“JADES-GS-z14-0 now becomes the archetype of this phenomenon,” said Stefano Carniani, member of the JADES collaboration team, Scuola Normale Superiore. “It’s amazing that the Universe can form such a galaxy in just 300 million years.”

JADES-GS-z14-0 brought some surprises

Not everything about JADES-GS-z14-0 was immediately clear to the JADES team, and some elements may confuse our picture of the early cosmos.

When it was first detected, the primordial galaxy was so close to a nearby foreground galaxy that the team suspected they might be celestial neighbors. This idea was dispelled in October last year, when the JADES crew spent five days performing an in-depth analysis of JADES-GS-z14-0 with NIRCam. Applying filters specifically tailored to identify early galaxies confirmed the extreme distance of JADES-GS-z14-0.

“We just couldn’t see any plausible way to explain this galaxy as just a neighbor of the nearest galaxy,” said Kevin Hainline, JADES team member and researcher at the University of Arizona.

The galaxy also surprised its discoverers because its light is even redder than expected. This is because the light from JADES-GS-z14-0 is being “reddened” by the dust within it, which will become the building blocks of stars that will help this galaxy grow even larger.

Another surprise was the discovery of oxygen in JADES-GS-z14-0. Elements heavier than hydrogen and helium are forged by stars during their lives and beyond distributed throughout the galaxies when these stars explode. The observation of oxygen in JADES-GS-z14-0 may indicate that at least a generation of stars already lived and died in this very primitive galaxy.

“All of these observations, together, tell us that JADES-GS-z14-0 is not like the types of galaxies that have been predicted by theoretical models and computer simulations to exist in the early universe,” said JADES researcher Jake Helton, from Steward. Observatory and the University of Arizona said. “Given the observed brightness of the source, we can predict how it might grow over cosmic time, and so far we have found no suitable analogue in the hundreds of other galaxies we have observed at high redshift in our research.”

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Helton added that given the relatively small region of the sky that JWST searched to find JADES-GS-z14-0, its discovery has profound implications for the predicted number of bright galaxies we see in the early Universe.

“Astronomers are likely to find many of these luminous galaxies, possibly at even earlier times, during the next decade with JWST,” he concluded. “We are excited to see the extraordinary diversity of galaxies that existed in the cosmic dawn!”