Steph Deschamps / July 21, 2022
Just one week after the revelation of the first images from the James Webb Space Telescope, the most powerful telescope ever designed, it may 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 observed record, Rohan Naidu of the Harvard Astrophysics Center told AFP.
He is the lead author of a study analyzing publicly available data from James Webb's first ongoing observations, posted online for all astronomers around the world.
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 away means going back in time. For example, the light from the Sun takes eight minutes to reach us, so we see it as it was eight minutes ago. By looking as far as possible, we can perceive the light as it was emitted billions of years ago.
The light of 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This study has not yet been peer-reviewed, but published as a preprint in order to be quickly accessible to the expert community.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 publication in the near future, said Rohan Naidu.
Records in astronomy are already shaky, tweeted Thomas Zurbuchen, Nasa's associate administrator for science. Yes, I tend to only applaud when faced with peer-reviewed scientific results. But this is very promising! he added of the study.
Another research team also concluded the same results, according to Rohan Naidu, which gives him confidence.
The galaxy was observed by the NiRcam instrument, and detected in what is called a deep field, which is a wider image taken with a long exposure time to detect the faintest glow.
The particularity of James Webb is that it only works in the infrared. The light emitted by the oldest objects has stretched and reddened on the way, passing in this wavelength not visible to the human eye.
To get an image of this galaxy, the data were translated into the visible spectrum: it appears as a circular red shape, and white in its center. A blurred point in the infinity of the cosmos.