James Webb would have allowed a first discovery: the most distant galaxy ever observed

James Webb would have allowed a first discovery: the most distant galaxy ever observed

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Just a week after the reveal of the first images of the James Webb Space Telescope, the most powerful ever designed, it may already have found the most distant galaxy ever observed.

Named GLASS-z13, it appears to us as it was only about 300 million years after the Big Bang, 100 million years younger than the previous record observed, Rohan Naidu, from the Center told AFP. of Astrophysics from Harvard. He is the lead author of a study analyzing data from the early observations of James Webb, which is currently underway. These data are posted online for all astronomers on the planet.

To see far, that is to say to go back in time

One of the main missions of this brand new telescope is to observe the first galaxies formed after the Big Bang, which occurred 13.8 billion years ago.

In astronomy, seeing far is like going back in time. Sunlight, for example, takes eight minutes to reach us, so we see it as it was eight minutes ago. By looking as far as possible, we can therefore perceive objects as they were billions of years ago. The light from this galaxy was emitted 13.5 billion years ago.

This study has not yet been peer-reviewed, but published as a “preprint” in order to be quickly accessible to the expert community. It has been submitted to a scientific journal for forthcoming publication, said Rohan Naidu. But already, many astronomers enthusiastically commented on this discovery on social networks.

Read also: The history of our Universe revealed by the James Webb telescope

“Records in astronomy are already faltering,” tweeted Thomas Zurbuchen, NASA associate administrator in charge of science. “Yes, I tend to applaud only in the face of peer-reviewed scientific results. But this is very promising!”, he added about the study.

Another research team also concluded the same results, according to Rohan Naidu, which “gives him confidence”.

An image invisible to the human eye

The galaxy was observed by James Webb’s NiRcam instrument, and detected on what is called a “deep field”, i.e. a wider image taken with a long exposure time in order to detect the faintest lights.

The peculiarity of James Webb is to work only in the infrared. Light emitted by older objects stretched and “reddened” along the way, passing into that wavelength not visible to the human eye. To draw an image of this galaxy, the data has therefore been “translated” into the visible spectrum: it then appears as a red circular shape, rather blurred, and white in its center.

In reality, the twenty or so researchers who took part in the study studied two galaxies, the other being called GLASS-z11, which is less distant. They have surprising characteristics, for the little that we already know: “They appear quite massive”, according to Rohan Naidu, and this from “very shortly after the Big Bang”. “It’s something we don’t really understand,” he added.

“There is still work”

When exactly did they form? Impossible to say at the moment. “There is still work to do,” said the researcher. He and his colleagues have requested more observing time with the telescope to perform spectroscopic analyzes — a technique for determining the properties of a distant object by analyzing the light captured. This should confirm their distance.

The James Webb Telescope was launched into space about six months ago. Worth $10 billion, it was placed 1.5 million kilometers from us. It has enough fuel to run for 20 years. Astronomers thus expect to be inundated with new cosmic discoveries for a long time to come.

Read also: The James Webb Telescope will soon deliver ‘the deepest image ever taken of our universe’


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