Four Webb Telescope detected around distant galaxies

Four Webb Telescope detected around distant galaxies

Astronomers found these two distant galaxies in the same small patch of sky. They estimate that the correct event dates back to 300 million years after the Big Bang.Credit: JWST GLASS Survey NASA/CSA/ESA/STScI; Pascal Oche / University of Geneva

NASA has built its newest James Webb Space Telescope, a peer into the distant universe and back to the dawn of history — and it’s already doing so in an amazing way. In the past two weeks since Webb’s first scientific images and data were made available to astronomers, they have reported a torrent of preliminary results, including several contenders for what may be the most distant galaxy ever seen.

Webb’s images reveal a large number of shimmering galaxies in the distant universe, appearing as they appeared a few hundred million years after the Big Bang 13.8 billion years ago. That telescope’s amazingly sharp images shattered astronomers’ preconceptions about the early universe.

“We had an idea of ​​what the galaxies were in this [distances] “It’s going to look like the shape and the amount of detail we’ll be able to see, but I think the reality is a bit mind boggling,” says Jehan Kartaltepe, an astronomer at Rochester Institute of Technology in New York.

Here are some of the things astronomers learn from Webb’s early observations.

There are a lot of galaxies out there.

Because Webb detects infrared light and because the expansion of the universe expands light to red wavelengths, the telescope is well suited for discovering galaxies that formed early in the history of the universe. In his first observational programs, which began in June, Webb discovered many distant galaxies that lie out of reach of other observatories, such as the Hubble Space Telescope.

“It points to what many of us have argued, that there are galaxies beyond what we saw with Hubble,” says Richard Ellis, an astronomer at University College London.

The era of the first galaxies began at the “cosmic dawn”, and may have begun about 250 million years after the Big Bang, when the first stars formed and lit up the universe. Later generations of stars coalesced into galaxies, the faint red spots that Webb began to discover.

Many web images are strewn with never-before-seen galaxies in the distant universe. “There is hardly any empty space devoid of anything,” Kartaltepe says.

One study combed data from many of the distant galactic domains that Webb has observed so far, to analyze the rate at which stars formed in the early universe. He found 44 previously unknown galaxies dating back less than 300 million years to the Big Bang. Combined with 11 previously known galaxies, the results show that there were a large number of star-forming galaxies in the early universe.1. The results “reaffirm the enormous potential of the future.” [Webb] The team, led by Callum Dunant of the University of Edinburgh, UK, wrote in a post on the arXiv preprint server.

Several galaxies are vying for the title of “farthest”.

Perhaps the most prevalent rush has been that of research teams vying to locate the most distant galaxy in Webb’s data. A number of candidates have been spotted and will need confirmation by further studies, but all of them will break Hubble’s record for the most distant galaxy, which was about 400 million years after the Big Bang.2And the3.

Pixelated image of Macy's Galaxy

Macy’s Galaxy: Astronomer Stephen Finkelstein named this distant galaxy after his daughter. It is estimated to date back to 280 million years after the Big Bang.Credit: Stephen Finkelstein (Utah Austin), Michaela Bagley (Utah Austin), Casey Papovich (Texas A&M) and the CEERS team

A competitor appeared in a Webb study called GLASS that included another galaxy, slightly less distant, in the same image4. “The fact that we found these two bright galaxies was really surprising,” says Marco Castellano, an astronomer at the National Institute of Astrophysics in Rome. He and his colleagues had not expected to find such distant galaxies in this small patch of sky. A second team also independently observed the two galaxies5.

Astronomers characterize the distance of galaxies by a scale known as the redshift, which determines how far the galaxy’s light has shifted to red wavelengths. The greater the redshift, the further away the galaxy. The GLASS filter has a redshift of 13. But on July 25 and 26, days after astronomers reported on GLASS galaxies, papers claiming redshift flooded atop the arXiv prepress server. “This is just the beginning,” says Rohan Naidoo, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.

One candidate, with a redshift of 14, appeared in a survey called CEERS, one of Webb’s most well-known early projects. CEERS principal investigator Stephen Finkelstein of the University of Texas at Austin named Maisie’s Galaxy, after his daughter6. Another study looked at the same first field image of Webb, released by US President Joe Biden on July 11, and found two possible galaxies at a redshift of 16, placing them just 250 million years after the Big Bang.Seven. Other arXiv papers predict other candidates, even redshifts of up to 20 .8.

Some of the early galaxies are surprisingly complex.

It also turns out that the distant Webb galaxies have more structure than astronomers expected.

Study of Webb’s first deep-field image has revealed a surprisingly large number of distant disk-shaped galaxies9. Using Hubble, astronomers have concluded that distant galaxies are more irregularly shaped than nearby galaxies, which, like the Milky Way, often display regular shapes like disks. The theory was that early galaxies were often distorted by interactions with neighboring galaxies. But Webb’s observations indicate that there are up to 10 times more disk-shaped galaxies than previously thought.

The first deep-field image from the James Webb Space Telescope

US President Joe Biden released this in-depth photo on July 11 – the first publicly disclosed science view of Webb.Credit: NASA, ESA, ASC, and STScI

“Thanks to James Webb’s accuracy, we can see that galaxies have disks much earlier than we thought,” says Alison Kirkpatrick, an astronomer at the University of Kansas in Lawrence. It’s a problem, she says, because it goes against previous theories of galactic evolution. “We’ll have to find out.”

The preprint manuscript indicates that massive galaxies formed much earlier in the universe than previously known. A team led by Ivo Labe of Swinburne University of Technology in Melbourne, Australia, reports the presence of seven massive galaxies in the CEERS field, with a redshift between 7 and 10ten. The scientists wrote: “We conclude that the central regions of at least some massive galaxies were already in existence to a large extent 500 million years after the Big Bang, and that the formation of megagalaxies began very early in the history of the Earth. Universe”.

Studies of galactic chemistry also show a rich and complex picture emerging from Webb’s data. Analysis of the first deep-field image examined light emitted by galaxies at a redshift of 5 or more. (The spectral lines that appear at different wavelengths of light are related to the chemical elements that make up galaxies.) He found an amazing wealth of elements such as oxygen11. Astronomers thought the chemical fertilization process – in which stars fuse hydrogen and helium to form heavier elements – took some time, but finding that it occurs in early galaxies “will rethink the rate at which stars form.” , says Kirkpatrick.

Closer galaxies are smaller than expected.

Webb’s surprises continue a little later in the evolution of the universe. One study looked at Webb’s observations of the “cosmic back,” the time frame about 3 billion years after the Big Bang. This is the time when star formation in the universe reached its peak and produced the most light.

Wren Suess, an astronomer at the University of California, Santa Cruz, compared Hubble images of galaxies at cosmic noon with Web images of the same galaxies. At the infrared wavelengths detected by Webb, most massive galaxies appeared much smaller than in the Hubble images.12. “It potentially changes our whole view of how the size of galaxies changes over time,” says Suess. Hubble studies suggested that galaxies start out small and get bigger over time, but Webb’s results suggest that Hubble didn’t have the big picture, so the evolution of galaxies may be more complex than scientists realize.

With Webb at the start of a planned 20-plus year career, astronomers know they have plenty of changes ahead. “Right now, I find myself lying awake at 3 a.m. wondering if everything I did was wrong,” Kirkpatrick says.

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