An international team of astronomers has announced the discovery of two of the earliest and most distant galaxies known. The light from both comes just 300 million years after the Big Bang and was only possible to observe thanks to the power of the James Webb Space Telescope (JWST).
The galaxies are located in a region near the Hubble Ultra Deep Field, famous observations from the Hubble Space Telescope showing some of the most distant galaxies known at the time. JWST’s larger mirrors and infrared capabilities allowed astronomers to see even further into the universe.
“These galaxies join a small but growing population of galaxies from the first half billion years of cosmic history where we can really probe the stellar populations and distinctive patterns of chemical elements within them,” Dr Francesco D’Eugenio of the Kavli Institute for Cosmology. at the University of Cambridge, one of the team behind the discovery, said in a statement.
The results are part of the JWST Advanced Extragalactic Deep Survey (JADES) and they are known as JADES-GS-z14-0 and JADES-GS-z14-1, with the former slightly more distant than the latter.
The team was able to conduct a spectroscopic study of the galaxies, refracting their light into a rainbow. Using this rainbow, researchers were able to figure out how far away they are and what kind of chemical elements were present. This is possible because chemical elements interact with light at specific wavelengths.
And that’s not all. Due to the expansion of the universe, light is redshifted. This is similar to the Doppler effect, which changes the pitch of an ambulance siren if the vehicle is approaching or receding. In the case of these galaxies, their light extends to extreme wavelengths.
“We’re seeing additional emission from hydrogen and possibly oxygen atoms, as is common in star-forming galaxies, but here it’s shifted to an unprecedented wavelength,” said Jakob Helton, a graduate student at the University of Arizona and the main author of one. of documents detailing the disclosure.
JADES-GS-z14-0 is small compared to the Milky Way, but powerful. It is 1,600 light-years across and is forming stars at a rate 20 times faster than our quiescent galaxy. Before JWST, astronomers didn’t expect galaxies to get big, bright and massive very quickly, but galaxies like this suggest that this is definitely one way they can grow.
“JADES-GS-z14-0 now becomes the archetype of this phenomenon,” said Dr Stefano Carniani of the Scuola Normale Superiore in Pisa, lead author on the discovery paper. “It’s amazing that the Universe can create such a galaxy in just 300 million years.”
JWST is designed to search for the most distant galaxies yet discovered, so expect this current record holder to be replaced relatively soon. These observations suggest that objects much closer to the Big Bang may soon be found.
“We could have detected this galaxy even if it was 10 times fainter, which means we could see other examples even earlier in the Universe – perhaps in the first 200 million years,” said Brant Robertson, professor of astronomy and astrophysics at the University. of California-Santa Cruz, and lead author of a third paper on the team’s study of the evolution of these galaxies. “The early universe has so much more to offer.”
Papers related to the discovery are awaiting peer review, but have been posted on arXiv. The Carniani paper confirmed the distance, the Helton paper deals with galactic properties, and the Robertson paper provides insight into how such a galaxy managed to grow so large in such a short time.