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 only about 300 million years after the big bang, 100 million years younger than the previous record observed, said Rohan Naidu of the Smithson Center for Astrophysics. from Harvard.
He is the main author of a study analyzing data from the first observations of James-Webb, currently in progress. These data are posted online for all astronomers on the planet.
Paper day! “Two Remarkably Luminous Galaxy Candidates at z~11-13 Revealed by the Just Wonderful Space Telescope”. T… https://t.co/BmU5AGvYYF
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 thus see objects as they were billions of years ago. The light from this galaxy was emitted 13.5 billion years ago.
A red circular shape
This study has not yet been peer reviewed, but published as preprint, in order to be quickly accessible to the community of experts. 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 concluded with the same results, according to Rohan Naidu, which “give confidence”.
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 glows.
The peculiarity of James-Webb is to operate only in the infrared. The light emitted by the oldest objects has stretched and “blushed” along the way, passing through this wavelength which is not visible to the human eye. To draw an image of this galaxy, the data was therefore “translated” in the visible spectrum: it then appears as a red circular shape, rather blurred, and white in its center.
“There is still work”
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, from “very soon 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”, 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 collected. 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 twenty years.
