James Webb Space Telescope finds 2 of the most distant galaxies ever seen

By Keith Cooper
Published November 14, 2023

These two galaxies, magnified by a gravitational lens, have properties that support the basic picture of galaxy formation as described in the Big Bang theory.

pandora cluster.jpeg
The JWST's view of Pandora's Cluster. This is the cluster that served as a gravitational lens for the new galactic findings. (Image credit: NASA, ESA, CSA, I. Labbe (Swinburne University of Technology), R. Bezanson (University of Pittsburgh), A. Pagan (STScI))

The second and fourth most distant galaxies ever seen have been spotted by the eagle eye of the James Webb Space Telescope (JWST), supporting the basic picture of galaxy formation as described by the Big Bang theory.

The discovery was made possible thanks to a huge helping hand from a massive gravitational lens in the form of the galaxy cluster known as Abell 2744, nicknamed Pandora's Cluster, which is located about 3.5 billion light-years away from us. The immense gravity of the cluster warps the very fabric of space-timesufficiently to magnify the light of more faraway galaxies.

Using the James Webb Space Telescope to search for early galaxies magnified by this cosmic lens, Bingjie Wang of the Penn State Eberly College of Science and member of the JWST UNCOVER (Ultradeep NIRSpec and NIRCam Observations before the Epoch of Reionization) team discovered two of the highest redshift galaxies ever seen.

( James Webb Space Telescope confirms 'Maisie's galaxy' is one of the earliest ever seen )

Cosmological redshift is the stretching of light wavelengths, provoked by the continuous expansion of the universe. The more distant a galaxy is, the more the universe had expanded while that galaxy’s light traveled across space to reach us, and therefore, the more the wavelengths of that light are stretched. As wavelengths get stretched out in this manner, they go from tighter, blueish ones to redder ones, eventually falling into the invisible, infrared region of the electromagnetic spectrum. Galaxies that existed just between 300 and 400 million years after the Big Bang have had their light stretched into those infrared wavelengths that can't be seen by humans, but can indeed be detected by the JWST’s Near-Infrared Camera (NIRCam) and Near-Infrared Spectrometer (NIRSPec).

Wang and her team were able to identify the lensed images of two high-redshift galaxies. One, designated UNCOVER-z13 ("z" is shorthand for "redshift"), has a redshift of 13.079, confirming it to be the second most distant galaxy known. (The most distant confirmed galaxy is JADES-GS-z13-0, which was also discovered by the JWST in 2022 and has a redshift of 13.2.) We see UNCOVER-z13 as it existed just 330 million years after the Big Bang.

The other galaxy recently discovered, UNCOVER-z12, has a redshift of 12.393, placing it in fourth place in the all-time list of most distant galaxies. We see this realm as it was just 350 million years after the Big Bang.

abell 2744.jpeg
An image of Abell 2744, Pandora’s Cluster, with the two high-redshift galaxies discovered by the JWST seen as insets. (Image credit: Cluster image: NASA/UNCOVER (Bezanson et al.); Insets: NASA/UNCOVER (Wang et al.); Composition: Dani Zemba/Penn State.)

What marks the two UNCOVER galaxies out as different is their appearance. Other galaxies seen at similarly high redshifts seem to be point-like, indicating they are very small — just a few hundreds of light years across. The UNCOVER galaxies, on the other hand, have structure.

"Previously discovered galaxies at these distances … appear as a dot in our images," Wang said in a statement. "But one of ours appears elongated, almost like a peanut, and the other looks like a fluffy ball."

These galaxies are also bigger, with UNCOVER-z12 sporting an edge-on disk about 2,000 light years across, which is six times larger than other galaxies seen in this era.

"It is unclear if the difference in size is due to how the stars formed or what happened to them after they formed, but the diversity in the galaxy properties is really interesting," said Wang. "These early galaxies are expected to have formed out of similar materials, but already they are showing signs of being very different than one another."

Although the dichotomy in galaxy properties, even at this early stage in the universe, is eye-opening, both of the newfound realms have general characteristics that are strongly supportive of the Big Bang model. This model describes how, in the aftermath of our universe's creation, galaxies began life small before growing rapidly through mergers with other galaxies and gas clouds.

This growth, in turn, spurred more star formation, which ultimately increased the abundance and variety of elements contained within the young galaxies, introducing substances to them that are heavier than hydrogen and helium. The galaxies uncovered by UNCOVER — if you’ll pardon the pun — are young, small, have a low abundance of heavy elements and are actively forming stars, all of which supports "the whole paradigm of the Big Bang theory," Joel Leja, who is an assistant professor of astronomy and astrophysics at Penn State University and a co-researcher on Wang’s team, said in the statement.

Interestingly, the JWST has the ability to see even higher redshift galaxies than UNCOVER-z13 and -z12, meaning they'd be even younger — but it didn’t detect any being lensed by the Pandora Cluster. "That could mean that galaxies just didn’t form before that time and that we’re not going to find anything farther away," said Leja. "Or it could mean we didn’t get lucky enough with our small window."

Astronomers will keep looking, using a multitude of lensing clusters to open up new windows into the deep universe in search of some of the first galaxies.

The discovery was reported on Monday (Nov. 13) in Astrophysical Journal Letters.

See: https://www.space.com/james-webb-space-telescope-distant-galaxies

In the first few months of operations, imaging from the James Webb Space Telescope (JWST) has been used to identify tens of candidates of galaxies at redshift (z) greater than 10, less than 450 million years after the Big Bang. However, none of such candidates has yet been confirmed spectroscopically, leaving open the possibility that they are actually low-redshift interlopers. Here we present spectroscopic confirmation and analysis of four galaxies unambiguously detected at redshift 10.3 ≤ z ≤ 13.2, previously selected from JWST Near Infrared Camera imaging. The spectra reveal that these primeval galaxies are metal poor, have masses on the order of about 107–108 solar masses and young ages. The damping wings that shape the continuum close to the Lyman edge provide constraints on the neutral hydrogen fraction of the intergalactic medium from normal star-forming galaxies. These findings demonstrate the rapid emergence of the first generations of galaxies at cosmic dawn.

See: https://www.nature.com/articles/s41550-023-01918-w

Stars beam brightly out of the darkness of space thanks to fusion, atoms melding together and releasing energy. But what if there’s another way to power a star?

A team of astrophysicists including Katherine Freese at The University of Texas at Austin analyzed images from the James Webb Space Telescope (JWST) and found three bright objects that might be “dark stars,” theoretical objects much bigger and brighter than our sun, powered by particles of dark matter annihilating. If confirmed, dark stars could reveal the nature of dark matter, one of the deepest unsolved problems in all of physics.

“Discovering a new type of star is pretty interesting all by itself, but discovering it’s dark matter that’s powering this—that would be huge,” said Freese, director of the Weinberg Institute for Theoretical Physics and the Jeff and Gail Kodosky Endowed Chair in Physics at UT Austin.

Although dark matter makes up about 25% of the universe, its nature has eluded scientists. Scientists believe it consists of a new type of elementary particle, and the hunt to detect such particles is on. Among the leading candidates are Weakly Interacting Massive Particles. When they collide, these particles annihilate themselves, depositing heat into collapsing clouds of hydrogen and converting them into brightly shining dark stars. The identification of supermassive dark stars would open up the possibility of learning about the dark matter based on their observed properties.

The research is published in the Proceedings of the National Academy of Sciences. Along with Freese, the co-authors are Cosmin Ilie and Jillian Paulin at Colgate University.

Follow-up observations from JWST of the objects’ spectroscopic properties — including dips or excess of light intensity in certain frequency bands — could help confirm whether these candidate objects are indeed dark stars.

Confirming the existence of dark stars might also help solve a problem created by JWST: There seem to be too many large galaxies too early in the universe to fit the predictions of the standard model of cosmology.

“It’s more likely that something within the standard model needs tuning, because proposing something entirely new, as we did, is always less probable,” Freese said. “But if some of these objects that look like early galaxies are actually dark stars, the simulations of galaxy formation agree better with observations.”

The three candidate dark stars (JADES-GS-z13-0, JADES-GS-z12-0, and JADES-GS-z11-0) were originally identified as galaxies in December 2022 by the JWST Advanced Deep Extragalactic Survey (JADES). Using spectroscopic analysis, the JADES team confirmed the objects were observed at times ranging from about 320 million to 400 million years after the Big Bang, making them some of the earliest objects ever seen.

“When we look at the James Webb data, there are two competing possibilities for these objects,” Freese said. “One is that they are galaxies containing millions of ordinary, population-III stars. The other is that they are dark stars. And believe it or not, one dark star has enough light to compete with an entire galaxy of stars.”

Dark stars could theoretically grow to be several million times the mass of our sun and up to 10 billion times as bright as the sun.

The idea for dark stars originated in a series of conversations between Freese and Doug Spolyar, at the time a graduate student at the University of California, Santa Cruz. They wondered: What does dark matter do to the first stars to form in the universe? Then they reached out to Paolo Gondolo, an astrophysicist at the University of Utah, who joined the team. After several years of development, they published their first paper on this theory in the journal Physical Review Letters in 2008.

Funding for this research was provided by the U.S. Department of Energy’s Office of High Energy Physics program and the Vetenskapsradet (Swedish Research Council) at the Oskar Klein Centre for Cosmoparticle Physics at Stockholm University.

Marc Airhart
College of Natural Sciences
p: 512-232-1066
e: mairhart@austin.utexas.edu

See: https://news.utexas.edu/2023/07/14/...es-glimpse-of-possible-first-ever-dark-stars/

Astrophysicists from the University of Texas at Austin found clues that three distant objects from the past that were initially identified as galaxies in December 2022 by the JWST Advanced Deep Extragalactic Survey (JADES) might actually be “dark stars.” How dark stars shine would be utterly different from our sun or any star in the known universe. Dark stars could be powered by yet unknown particles of dark matter annihilating each other, and therefore those theoretical objects would be much bigger and brighter than casual stars. Dark stars could also provide an explanation of how supermassive black holes in the centers of the galaxies formed and reveal the nature of dark matter, one of the deepest unsolved problems in physics.