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

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

Dubbed GLASS-z13, it appears to us to have formed only about 300 million years after the Big Bang, 100 million years younger than the previously observed record, Rohan Naidu of Harvard’s Center for Astrophysics told AFP. He is the lead author of a study analyzing data from James Webb’s early observations, which is currently underway. This data is published online for all astronomers on the planet.

Seeing far means going back in time

One of the main tasks of this brand new telescope is to observe the first galaxies to form after the Big Bang 13.8 billion years ago.

In astronomy, foresight is like traveling back in time. Sunlight, for example, takes eight minutes to reach us, so we see it as it was eight minutes ago. So, by looking as far as possible, we can see objects as they looked billions of years ago. The light from this galaxy was emitted 13.5 billion years ago.

This study has not yet been reviewed, but published as a “preprint” so that it can be quickly accessed by experts. It has been submitted to a scientific journal for forthcoming publication, Rohan Naidu said. But already many astronomers enthusiastically commented on this discovery in social networks.

Also read: The history of our universe revealed by the James Webb telescope

“The records in astronomy are already shattering,” tweeted Thomas Zurbuchen, NASA’s deputy administrator in charge of science. “Yes, I tend to applaud only in the face of peer-reviewed science. But this is very promising!” he added of the study.

Another research team also came to the same conclusions, according to Rohan Naidu, which “gives them confidence.”

An image invisible to the human eye

Observed by James Webb’s NiRcam instrument, the galaxy was captured in what is known as a ‘deep field’, a broader image taken with a long exposure time to reveal the faintest lights.

The peculiarity of James Webb is that he only works in the infrared range. The light emitted by older objects was stretched and “reddened” along the way, entering wavelengths invisible to the human eye. In order to draw a picture of this galaxy, the data was therefore “translated” into the visible spectrum: it then appears as a red circular shape, rather fuzzy, and white at its center.

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

“There is still work”

When exactly were they created? Impossible to say at the moment. “There is still a lot to do,” said the researcher. He and his colleagues have asked for more observing time with the telescope to perform spectroscopic analysis – a technique for determining the properties of a distant object by analyzing the light it collects. This should confirm their distance.

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

Also read: The James Webb telescope will soon provide “the deepest picture ever taken of our universe”.

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