James Webb Space Telescope reveals ancient galaxies were more structured than scientists thought
Sharmila Kuthunur
Tue, September 26, 2023
What did galaxies in the early universe look like? Surprisingly close to our own Milky Way, according to the latest findings from the James Webb Space Telescope (JWST), whose unprecedented infrared eye has been rewriting what we thought we knew about the early universe.
Astronomers have long thought that newly minted galaxies that began merging together just after the Big Bang, about 13.7 billion years ago, were too fragile to boast any noticeable structures like spiral arms, bars or rings. Those galactic features were thought to form during a time at least six billion years after the Big Bang. According to the new study, however, these delicate shapes could've manifested as early as 3.7 billion years after the Big Bang — which is almost at the beginning of the universe.
"Based on our results astronomers must rethink our understanding of the formation of the first galaxies and how galaxy evolution occurred over the past 10 billion years," Christopher Conselice, an astronomy professor at The University of Manchester in the U.K. and a co-author of the new study, said in a statement published Friday (Sept. 22).
The new findings come at the heels of another announcement presented by a different group of researchers, also based on JWST data, which showed these early galaxies produced far fewer heavy elements than previously expected. However, the relationship between a galaxy's chemical composition and its evolution into a well-defined structure is not very well understood.
Much of scientists' previous understanding on galaxy evolution came from data gathered by the Hubble Space Telescope (HST), which is legendary in its own right but still has only so much resolution. While the HST data showed early galaxies had irregular shapes (as was expected during galaxy mergers) higher resolution data from the JWST is peering deeper into the universe to reveal that those early galaxies actually had well-defined structures like our own Milky Way. The new findings were based on an analysis of 3,956 galaxies, which astronomers say is the biggest sample that has been studied thus far with JWST data.
Robert Lea
Mon, September 25, 2023
The James Webb Space Telescope (JWST) has discovered that galaxies in the early universe were cosmic rule-breakers. This discovery sheds light on how early galaxies evolved and the fundamental processes that shaped the universe as we see it today.
To discover the truth about these cosmic scofflaws, a team of astronomers used the JWST to gaze over 12 billion years back in time and observe galaxies as well as the rules they followed through cosmic history. The crew found that the same set of rules continuously prevailed, connecting the rate of star birth to galactic masses to chemical compositions. But these rules traced only so far back. The earliest galaxies defied them.
It was like the galaxies had a rulebook that they followed — but astonishingly, this cosmic rulebook appears to have undergone a dramatic rewrite during the universe’s infancy," Claudia Lagos, an associate professor at the University of Western Australia, said in a statement. "The most surprising discovery was that ancient galaxies produced far fewer heavy elements than we would have predicted based on what we know from galaxies that formed later."
This disparity hadn’t been spotted before because instruments used prior to the JWST hadn’t been powerful enough to see the chemical makeup of galaxies as far back as around 11 billion years ago. The JWST, however, allowed this team to look back to just a few hundred million years after the Big Bang, which showed a break in the relationship between star formation, mass and chemistry.
When did things get heavy for the cosmos?
When the universe first began to form the first stars and galaxies, it was filled with hydrogen and helium — the two lightest elements — with the former being the most dominant by far.
Only a smattering of heavier elements-which astronomers call “metals” existed until the first generation of stars forged them at their hearts and then dispersed them through the universe at the end of their lives via massive supernova explosions.
This material was eventually incorporated into the next generation of stars, meaning these stars, and thus the galaxies they sit in, had a higher concentration of metals — a measure called "metallicity." That process of metal enrichment has continued throughout the entire 13.8 billion years of cosmic history, meaning early galaxies are indeed expected to have lower metallicities than their modern counterparts.
But even factoring this in, the team found that the metallicity of early galaxies was still lower than expected. Much lower.
"Their chemical abundance was approximately four times lower than anticipated, based on the fundamental-metallicity relation observed in later galaxies," Lagos continued, explaining that the early galaxies observed by the team delivered even more surprises.
The team suggests the disparity may exist because galaxies just a few hundred million years after the Big Bang could still be intimately connected with the intergalactic medium — the wispy hot gas and dust that exists between galaxies.
"The early galaxies continually received new, pristine gas from their surroundings, with the gas influx diluting the heavy elements inside the galaxies, making them less concentrated," Lagos concluded.
As such, the team’s findings could challenge current models of galactic evolution and the mechanism that facilitated the development of the first galaxies.
The research was published on Sept. 21 in the journal Nature.
Sharmila Kuthunur
Tue, September 26, 2023
What did galaxies in the early universe look like? Surprisingly close to our own Milky Way, according to the latest findings from the James Webb Space Telescope (JWST), whose unprecedented infrared eye has been rewriting what we thought we knew about the early universe.
Astronomers have long thought that newly minted galaxies that began merging together just after the Big Bang, about 13.7 billion years ago, were too fragile to boast any noticeable structures like spiral arms, bars or rings. Those galactic features were thought to form during a time at least six billion years after the Big Bang. According to the new study, however, these delicate shapes could've manifested as early as 3.7 billion years after the Big Bang — which is almost at the beginning of the universe.
"Based on our results astronomers must rethink our understanding of the formation of the first galaxies and how galaxy evolution occurred over the past 10 billion years," Christopher Conselice, an astronomy professor at The University of Manchester in the U.K. and a co-author of the new study, said in a statement published Friday (Sept. 22).
The new findings come at the heels of another announcement presented by a different group of researchers, also based on JWST data, which showed these early galaxies produced far fewer heavy elements than previously expected. However, the relationship between a galaxy's chemical composition and its evolution into a well-defined structure is not very well understood.
Much of scientists' previous understanding on galaxy evolution came from data gathered by the Hubble Space Telescope (HST), which is legendary in its own right but still has only so much resolution. While the HST data showed early galaxies had irregular shapes (as was expected during galaxy mergers) higher resolution data from the JWST is peering deeper into the universe to reveal that those early galaxies actually had well-defined structures like our own Milky Way. The new findings were based on an analysis of 3,956 galaxies, which astronomers say is the biggest sample that has been studied thus far with JWST data.
"For over 30 years it was thought that these disk galaxies were rare in the early universe due to the common violent encounters that galaxies undergo," Leonardo Ferreira, an astrophysicist at the University of Victoria in Canada and the lead author of the new study, said in the same statement. "The fact that JWST finds so many is another sign of the power of this instrument and that the structures of galaxies form earlier in the Universe, much earlier in fact, than anyone had anticipated."
According to the new study, the team classified the sample set of close to 4,000 galaxies from the early universe by shape — like disks, point sources and spheroids. Team members further classified them as smooth or structured, with galaxies in the latter group featuring bursts of star formation and indications of mergers with other galaxies.
Results showed that relatively well-defined structures in the universe form a lot quicker than previously thought, following what is known as the Hubble Sequence, which is the standard classification of galaxies by their visual properties as ellipticals, lenticulars and spirals.
The latest findings suggest a need for new ideas that explain how galaxies evolved over the past 10 billion years.
This research is described in a paper published Sept. 22 in The Astrophysical Journal.
James Webb Space Telescope sees early galaxies defying 'cosmic rulebook' of star formation
According to the new study, the team classified the sample set of close to 4,000 galaxies from the early universe by shape — like disks, point sources and spheroids. Team members further classified them as smooth or structured, with galaxies in the latter group featuring bursts of star formation and indications of mergers with other galaxies.
Results showed that relatively well-defined structures in the universe form a lot quicker than previously thought, following what is known as the Hubble Sequence, which is the standard classification of galaxies by their visual properties as ellipticals, lenticulars and spirals.
The latest findings suggest a need for new ideas that explain how galaxies evolved over the past 10 billion years.
This research is described in a paper published Sept. 22 in The Astrophysical Journal.
James Webb Space Telescope sees early galaxies defying 'cosmic rulebook' of star formation
Robert Lea
Mon, September 25, 2023
The James Webb Space Telescope (JWST) has discovered that galaxies in the early universe were cosmic rule-breakers. This discovery sheds light on how early galaxies evolved and the fundamental processes that shaped the universe as we see it today.
To discover the truth about these cosmic scofflaws, a team of astronomers used the JWST to gaze over 12 billion years back in time and observe galaxies as well as the rules they followed through cosmic history. The crew found that the same set of rules continuously prevailed, connecting the rate of star birth to galactic masses to chemical compositions. But these rules traced only so far back. The earliest galaxies defied them.
It was like the galaxies had a rulebook that they followed — but astonishingly, this cosmic rulebook appears to have undergone a dramatic rewrite during the universe’s infancy," Claudia Lagos, an associate professor at the University of Western Australia, said in a statement. "The most surprising discovery was that ancient galaxies produced far fewer heavy elements than we would have predicted based on what we know from galaxies that formed later."
This disparity hadn’t been spotted before because instruments used prior to the JWST hadn’t been powerful enough to see the chemical makeup of galaxies as far back as around 11 billion years ago. The JWST, however, allowed this team to look back to just a few hundred million years after the Big Bang, which showed a break in the relationship between star formation, mass and chemistry.
When did things get heavy for the cosmos?
When the universe first began to form the first stars and galaxies, it was filled with hydrogen and helium — the two lightest elements — with the former being the most dominant by far.
Only a smattering of heavier elements-which astronomers call “metals” existed until the first generation of stars forged them at their hearts and then dispersed them through the universe at the end of their lives via massive supernova explosions.
This material was eventually incorporated into the next generation of stars, meaning these stars, and thus the galaxies they sit in, had a higher concentration of metals — a measure called "metallicity." That process of metal enrichment has continued throughout the entire 13.8 billion years of cosmic history, meaning early galaxies are indeed expected to have lower metallicities than their modern counterparts.
But even factoring this in, the team found that the metallicity of early galaxies was still lower than expected. Much lower.
"Their chemical abundance was approximately four times lower than anticipated, based on the fundamental-metallicity relation observed in later galaxies," Lagos continued, explaining that the early galaxies observed by the team delivered even more surprises.
The team suggests the disparity may exist because galaxies just a few hundred million years after the Big Bang could still be intimately connected with the intergalactic medium — the wispy hot gas and dust that exists between galaxies.
"The early galaxies continually received new, pristine gas from their surroundings, with the gas influx diluting the heavy elements inside the galaxies, making them less concentrated," Lagos concluded.
As such, the team’s findings could challenge current models of galactic evolution and the mechanism that facilitated the development of the first galaxies.
The research was published on Sept. 21 in the journal Nature.
Isaac Schultz
Tue, September 26, 2023
In the beginning, galaxies were lacking in chemical and metal abundances, according to a team of astronomers that recently used a telescope to study the ancient universe.
Though the galaxies in the quarter-billion years seemed to follow the rules established by younger, previously observed galaxies regarding star formation rate and stellar mass, they had only a quarter the chemical abundance that was expected, the researchers found. The team’s research on the ancient galaxies was published last week in Nature Astronomy.
Until recently, the team noted, galaxies’ chemical abundances could only be reliably measured at redshifts of z=3.3 or less. But Webb allowed the recent team to measure such abundances at redshifts of z=7-10, or between 500 million years and 750 million years after the Big Bang.
The researchers used Webb’s far-reaching gaze to measure the rates of star formation, stellar masses, and chemical abundances of galaxies from the universe’s first few hundred million years of existence.
“The most surprising discovery was that ancient galaxies produced far fewer heavy elements than we would have predicted based on what we know from galaxies that formed later,” Lagos said. “The early galaxies continually received new, pristine gas from their surroundings, with the gas influx diluting the heavy elements inside the galaxies, making them less concentrated.”
The ancient galaxies aren’t even the most ancient Webb has seen. Last November the telescope spotted two galaxies with redshifts of approximately 10.25 and 12.5, rivalling the age of Maisie’s Galaxy, another galaxy spotted by Webb with a redshift of 11.8, or an age of about 13.4 billion years. Our universe is about 13.77 billion years old.
One of Webb’s main tasks is scrutinizing these ancient galaxies, to understand how they took form and evolved. Many of the ancient galaxies Webb has seen appear surprisingly mature, given their appearance in a nascent universe.
But the new research indicates the galaxies still have their secrets—in this case, an evident lack of heavy elements. More observations by Webb could help explain how these galaxies took shape, but expect more mysteries to arise on scientists’ search for clarity.
Ancient supernova in James Webb telescope image could help solve one of the universe's biggest mysteries
Harry Baker
Tue, September 26, 2023
A JWST image of two large bright galaxies ringed in orange light from a distant supernova.
A rare, warped supernova that appears three times in a single image could help researchers finally solve a long-standing inconsistency about the universe that has threatened to unravel our understanding of the cosmos, one expert claims.
The type 1a supernova, named SN H0pe, was first discovered lurking in photographs captured by NASA's James Webb Space Telescope (JWST) in March. In these images, the exploding star can be seen as an arc of orange light with three bright points that surround part of the galaxy cluster PLCK G165.7+67.0 (G165), which is around 4.5 billion light-years from Earth.
The light arc is the result of gravitational lensing — an effect caused when light from a distant object, such as a supernova, passes through space-time that has been warped by the gravity of a massive foreground object, like a large galaxy, that is positioned directly between the distant object and the observer. This also magnifies the distant object, making it easier for researchers to analyze.
The three bright spots in the arc around G165 make it seem like there are three separate light sources being visually manipulated, or lensed by the foreground galaxy. But in reality, the supernova, which is located around 16 billion light-years from us, has been duplicated twice by the lensing effect.
Related: Distortions in space-time could put Einstein's theory of relativity to the ultimate test
In a new article published on BigThink.com on Sept. 20, astrophysicist and science communicator Ethan Siegel, who was not involved in the study, wrote that SN H0pe could help solve a longstanding inconsistency about the expansion of the universe — the "Hubble tension."
The Hubble tension is based on a discrepancy between the two main ways of estimating the rate of the universe's expansion, known as the Hubble constant. The first method, which involves measuring expansion using the cosmic microwave background (CMB) — leftover radiation from the Big Bang that was first detected in 1964 — comes out with one value for the Hubble constant. But the second method, which involves measuring how far specific objects, such as galaxies and supernovas, are moving away from us, consistently comes out with a slightly higher value.
This problem has confused scientists for decades because there is no clear reason why one method should produce a different result from the other, Siegel wrote. The conundrum has even caused some researchers to declare it a crisis in cosmology.
SN H0pe could help solve the Hubble tension because it is a type 1a supernova, which astronomers refer to as a "standard candle" — an incredibly reliable reference point from which we can measure the universe's expansion, Siegel wrote.
Related: The universe could stop expanding 'remarkably soon', study suggests
Type 1a supernovas involve a white dwarf star stealing matter from a binary partner star, before reaching critical mass and exploding. These bright explosions all have near-equal initial luminosity and dim over time at the same rate. By comparing these standard candles at various distances from Earth, scientists can work out exactly how fast they are moving away from us and can then deduce the expansion rate of the universe.
SN H0pe is a particularly important standard candle because it is the second most distant type 1a supernova ever detected, Siegel wrote. The strong gravitational lensing and duplication in the new images also give researchers more information to work with than normal, he added.
The idea of using duplicated supernovae to tackle the problem of Hubble tension is not new. In May, scientists used data from a reappearing, quadruple-lensed supernova named Refsdal to calculate a new value for the Hubble constant. Although this still differed from the value calculated using the CMB, the difference between the two was reduced, suggesting that they could one day match up.
It is currently unclear whether SN H0pe can be used to calculate an even more reliable value for the Hubble constant. But researchers are confident that if JWST's keen eye can continue to pick out more distant standard candles, the problem of Hubble tension may finally be solved.
Stunningly perfect 'Einstein ring' snapped by James Webb telescope is most distant gravitationally lensed object ever seen
Harry Baker
Tue, September 26, 2023
In the field of one of JWST's largest-area surveys, COSMOS-Web, an Einstein ring was discovered around a compact, distant galaxy. It turns out to be the most distant gravitational lens ever discovered by a few billion light-years.
Photos snapped by the James Webb Space Telescope (JWST) have revealed the farthest-ever example of an "Einstein ring." The record-breaking halo of warped light, which is a whopping 21 billion light-years away, is unusually perfect and surrounds a mysteriously dense galaxy.
An Einstein ring is an extremely rare type of gravitationally lensed object that was first predicted by Albert Einstein's theory of relativity. Gravitational lensing occurs when the immense gravity of a massive foreground object, such as a galaxy cluster or a black hole, warps space-time around itself; light emitted by more distant objects, such as galaxies or supernovas, that passes through this warped space-time also appears curved and warped from our perspective on Earth.
This effect also magnifies the light of the object being lensed, similar to how a magnifying glass works, allowing astronomers to study distant objects in greater detail than is normally possible. Most gravitationally lensed objects form arcs or partial rings that surround the foreground object. But a true Einstein ring forms a complete circle around the closer entity, which is possible only when the distant object, foreground object and observer are perfectly aligned.
In a new study uploaded Sept. 14 to the preprint server arXiv and accepted for publication in the journal Nature Astronomy, researchers discovered the new eerily circular Einstein ring, named JWST-ER1, within the COSMOS-Web survey, a detailed map of more than 500,000 galaxies captured during a 200-hour continuous JWST observation.
JWST-ER1 has two parts: JWST-ER1g, the compact galaxy that acts as the lensing object in the foreground; and JWST-ER1r, the light from a more distant galaxy that forms the luminous ring. JWST-ER1g is located around 17 billion light-years from Earth, while JWST-ER1r is another 4 billion light-years farther away. Until now, the farthest detected lensing object was around 14.7 billion light-years away, according to BigThink.com. (While the age of the universe itself is estimated to be about 13.7 billion years, the universe's constant expansion means that light from the oldest objects must travel much farther than this to reach our telescopes).
Related: Dark matter's secret identity could be hiding in distorted 'Einstein rings'
Thanks to the complete ring of JWST-ER1, researchers calculated the mass of the lensing galaxy by seeing how much it had warped space-time around itself. This revealed that the galaxy has a mass equivalent to around 650 billion suns, which makes it unusually dense for its size. Some of this extra mass can be explained by dark matter, the mysterious, invisible matter that makes up around 85% of all matter in the universe. But even then, it is unlikely that there are enough stars to account for the rest of the galaxy's heft based on the researchers' calculations.
"Additional mass is needed to explain the lensing results," but it is not exactly clear what this mass is, the researchers wrote in the paper.
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Other, similarly old and equally dense galaxies have been detected before, which suggests there is something common about these ancient star factories that makes them so massive. One explanation is that these galaxies harbor much more dark matter than expected, while another theory suggests that they may have more small-mass stars lurking within them than younger galaxies do. But more work is needed to find out.
This is not the first true Einstein ring spotted by JWST. In September 2022, a Reddit user discovered a perfectly circular ring of light from the galaxy JO418, located around 12 billion light-years from Earth, lensed around a closer galaxy.
JWST has also utilized gravitational lensing to snap the most distant star ever detected and one of the universe's oldest galaxies.
Nasa spots shocking number of galaxies like our own in early universe
Andrew Griffin
Mon, September 25, 2023
The finding will prompt us to entirely rethink our understanding of how the universe formed the structures that surround us.
Looking deep into space, scientists found that the galaxies we see in the early universe are much more like our own Milky Way than was thought possible.
A team of international researchers including those at The University of Manchester and University of Victoria in Canada, used the James Webb Space Telescope (JWST) to discover that galaxies like the Milky Way are 10 times more common than what was believed based on previous observations with the Hubble Space Telescope.
Many of these galaxies formed some 10 billion years ago or longer, going far back into the history of the universe.
The Milky Way is a typical disk galaxy, with a shape similar to a pancake or compact disc, rotating about its centre and often containing spiral arms.
These galaxies might be the kind where life can develop given the nature of their formation history, experts suggest.
Astronomers previously considered these types of galaxies too fragile to exist in the early universe when galaxy mergers were more common, destroying what was thought to be their delicate shapes.
Christopher Conselice, professor of extragalactic astronomy at The University of Manchester, said: “Using the Hubble Space Telescope we thought that disc galaxies were almost non-existent until the universe was about six billion years old, these new JWST results push the time these Milky Way-like galaxies form to almost the beginning of the universe.”
He added: “These JWST results show that disc galaxies like our own Milky Way, are the most common type of galaxy in the universe.
“This implies that most stars exist and form within these galaxies which is changing our complete understanding of how galaxy formation occurs.
“These results also suggest important questions about dark matter in the early universe which we know very little about.”
“Based on our results, astronomers must rethink our understanding of the formation of the first galaxies and how galaxy evolution occurred over the past 10 billion years.”
The researchers say their findings, published in the Astrophysical Journal, completely overturn the existing understanding of how scientists think the universe evolves, and the scientists say new ideas need to be considered.
Lead author Leonardo Ferreira, from the University of Victoria, said: “For over 30 years it was thought that these disc galaxies were rare in the early universe due to the common violent encounters that galaxies undergo.
“The fact that JWST finds so many is another sign of the power of this instrument and that the structures of galaxies form earlier in the universe, much earlier in fact, than anyone had anticipated.”
The improved technology of JWST allows astronomers to see the true structure of these galaxies for the first time.
A paper describing the findings, ‘The JWST Hubble Sequence: The Rest-Frame Optical Evolution of Galaxy Structure at 1.5 The Astrophysical Journal.
Additional reporting by agencies
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