The James Webb Telescope (JWST, or Webb) has revealed hundreds of ancient galaxies that could have been among the universe’s first members — a jump from only a handful previously known to exist at the time.
As early as 600 million years after the great explosionThese very young galaxies boast complex structures and clusters of star formation, a new study reports. The study is part of an international collaboration called the JWST Advanced Deep Extragalactic Survey (JADES), which collected a month’s worth of observations from two small spots in the sky: one in the constellation Ursa Minor and the other in the direction of the Fornax cluster. Within this region were more than 700 newly discovered young galaxies that seemed to reveal the universe as soon as possible.
Kevin Heinlein, assistant research professor at Steward Observatory in Arizona and lead author of the new study: “If you take the entire universe and reduce it to a two-hour movie, you watch the first five minutes of the movie.” He said while announcing the discovery Monday (June 5) at the 242nd meeting of the American Astronomical Society in Albuquerque and online. “These are the galaxies that initiate the process of elemental formation and complexity that we see in the world around us today.”
These new discoveries have shed light on how the first galaxies and stars formed, creating a rich catalog of elements observed in the universe today.
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In those five minutes alone, which indicate that the universe is between 370 million and 650 million years old, Heinline’s and colleagues studying Webb’s data found 717 small galaxies—which turned out to be higher than previous predictions—all of which actually span thousands of galaxies. From light years away, complex mathematical structures, and birth stars into multiple clusters.
Heinline said statement. “Now, we can see that some of them are extended objects with visual structure.”
The two regions used in this study are collectively referred to as GOODS-South, which is short for Deep Scan of the Origins of the Great Observatoriesand has been extensively studied by almost all major space telescopes, including Hubblethe Chandra X-ray Observatory Spitzer is now retired from NASA.
Despite this earlier examination, 93% of the newly discovered galaxies Webb spotted during JADES had never been seen before.
“What we were seeing before were just brighter, more extreme examples of bright galaxies in the early Universe,” Heinlein said during his presentation on Monday. “We are now looking for more ordinary, everyday galaxies in a turbulent young universe.”
It has long been discussed how that messy and dusty environment was cleansed into the transparent universe we see today. One of the leading theories is that this stage in the evolution of the universe is called The era of reionizationoccurred about 400,000 years after the Big Bang, when the first generation of stars — thought to be between 30 and 300 times more massive and millions of times more luminous — formed and engulfed the murky universe. first light.
Ultraviolet starlight reionized the universe by splitting the abundant hydrogen atoms into protons and electrons, a process that continued until a billion years after the Big Bang. However, few astronomers say outflows from supermassive black holessimilar to that found in the heart of our Milky Way galaxy, it could be It causes UV rays to escape of galaxies, and thus played a more important role in cosmic evolution than previously thought.
Now, a second team from the JADES program that has been studying galaxies that existed between 500 to 850 million years after the Big Bang, or five to eight minutes into the two-hour movie describing the universe, thinks it has an answer to a long-standing question.
Ryan Endsley, a postdoctoral researcher at the University of Texas who led the second study, said at a news conference Monday. “Galaxies in the early Universe were generally chaotic in how they formed stars.”
Endsley’s team studied the signs star formation in those very early galaxies, which has provided insight into how starlight ionizes the gas within those galaxies. The team found that one in six galaxies at the time showed linear emission maxima in galactic spectra, a feature radiated by atoms ionized by starlight as they cool and merge with other particles.
These emission lines are evidence that the early galaxies were active in the birth of stars, which then pumped out “torrents of ultraviolet photons” into their own galaxies. In this way, the early stars of the universe became the main drivers of cosmic reionization, Endsley said.
“These extreme emission lines are relatively common in the early universe,” he said during his presentation. “Almost every galaxy we find shows unusually strong emission line signs that indicate intense recent star formation,” he added in the statement. “These early galaxies were very good at forming hot, massive stars.”
From the same emission lines, Endsley’s team also inferred that galaxies in the early universe generated stars in short bursts followed by periods of quiescence.
“Suddenly you’ll have dozens suns “This is really important for our understanding of how reionization occurs because these massive, hot stars were very efficient producers of these ultraviolet photons. We needed to ionize all the hydrogen in the early universe,” Endsley told reporters at Monday’s press conference.
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