Just a week after the revelation of the first images of the James Webb space telescope, the most powerful ever designed, it could already have found the most distant galaxy ever observed, which existed 13.5 billion years ago.
Named GLASS-z13, it appears to us as it was some 300 million years after the Big Bang, or 100 million years less than the previous record observed, Rohan Naidu, from the Center for Harvard Astrophysics.
He is the lead author of a study analyzing data from the early observations of James Webb, in progress. These data are posted online for all astronomers on the planet.
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. Light from the Sun takes, for example, eight minutes to reach us, and 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.
? JWST has potentially smashed records, spotting a galaxy which existed when the universe was a mere 300 million years old! The light from GLASS-z13 took 13.4 billion years to hit us, but the distance between us is now 33 billion light years due to the expansion of the universe! pic.twitter.com/5AcOBwHuO1
— Dr. James O’Donoghue (@physicsJ) July 20, 2022
The light from this observed galaxy was emitted 13.5 billion years ago.
This study has not yet been peer-reviewed, but it has been published as a preprint in order to be quickly accessible to the scientific community.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.
“Records in astronomy are already faltering,” tweeted Thomas Zurbuchen, NASA associate administrator for science. “Yes, I tend to only applaud peer-reviewed scientific results. But this is very promising! he added of the study.
Another research team also arrived at the same results, according to Rohan Naidu, which “gives him confidence”.
Fuzzy point in the cosmos
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 fainter lights.
The peculiarity of James Webb is to work only in the infrared. The light waves emitted by the most distant, and oldest objects, stretched and “reddened” along the way, passing in this 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 fuzzy, and white in its center.
The twenty or so researchers who took part in the study also studied another galaxy, called GLASS-z11, which is less distant.
Both 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.
When exactly did they form? Impossible to say at the moment.
“There is still work to do,” said the researcher. He and his colleagues asked for 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 dollars, it was placed 1.5 million kilometers from us in orbit around the Sun.
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.