Four new primordial galaxies have been discovered, and their existence has been confirmed, the light of which dates back to ‘only’ 350 million years after the Big Bang, or to the time when the age of the Universe was just 2 % of the current one. This is what emerged from the first data of the Jades research project carried out by the Webb space telescope, the result of a collaboration between NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA).
Launched into orbit just a year ago, the James Webb Space Telescope has already racked up a series of groundbreaking discoveries for the world of astrophysics, including this latest detection: 4 new galaxies (currently called GS-z10-0, GS- z11-0, GS-z12-0, GS-z13-0) very close to the time when the universe originated. This is the most accurate experimental data ever obtained from a telescope, both on the ground and in space.
The analysis of these data was conducted by a team of international astrophysicists (in Great Britain, by Emma Curtis-Lake of the University of Hertfordshire and Sandro Tacchella of the University of Cambridge; in the United States by Brant Robertson of the University of Santa Cruz). In Italy by Stefano Carniani, of the Scuola Normale Superiore of Pisa.
“The four galaxies observed with Webb are particularly interesting as they could represent the progenitors of the Milky Way – explains Carniani – The light that comes from them is mainly emitted by young stars, an indicator that confirms that we are observing the first evolutionary stages of these galaxies. In addition, data processing has allowed us to determine the size of these objects, which turned out to be about 500 times smaller than the Milky Way while forming new stars with an annual rate similar to that of our galaxy”.
Until now, astrophysicists could only hypothesize the existence of galaxies in the early stages of life of the Universe, while today the Webb telescope, thanks in particular to the Near-Infrared Spectrograph (NIRSpec), is able to transform hypotheses into certainties thanks to the acquisition of electromagnetic spectra. “Among other things, these spectra – adds Carniani – show exactly what we expected from primordial galaxies, namely that the light emitted at the shortest wavelengths is completely absorbed by neutral hydrogen in the early universe”.
“This research project – comments Emma Curtis-Lake – is essential to confirm that galaxies similar to the ones we observed actually populate the early universe. In other types of observations, in fact, the possibility of confusing a nearby astrophysical source is very high to the earth with a distant galaxy”.
The data on which this new discovery is based are the result of an international collaboration between research groups from 10 different countries. These groups, which have been involved in the development phases of two of the four instruments aboard the Webb Space Telescope (Near-Infrared Camera – NIRCam and Near-Infrared Spectrograph – NIRSpec), joined forces in 2015 to plan the Jades project ( JWST Advanced Deep Extragalactic Survey), one of the most ambitious observing programs of the Webb telescope aimed at the identification and subsequent study of the properties of galaxies and primordial black holes.
“It is difficult to fully understand the physics of galaxies without knowing the initial stages of their evolution – explains Sandro Tacchella -. As with human beings, the early stages of life of a galaxy have, in fact, a significant impact on subsequent development “.
“The Jades research project – concludes Carniani – is only at the beginning and during 2023 the Webb telescope will allow us to answer some of the questions still open in the field of astrophysics. Our goal is, first of all, to continue the research of the first galaxies by determining the mechanisms that led to their formation and evolution”.