An international team of astronomers has announced the detection of two of the earliest and most distant galaxies known. The light from both comes from just 300 million years after the Big Bang and it was only possible to observe them thanks to the power of the James Webb Space Telescope (JWST).
The galaxies are located in a region near the Hubble Ultra Deep Field. The famous Hubble Space Telescope observations show 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 investigate the stellar populations and the distinctive patterns of chemical elements within them,” says Dr. Francesco D’Eugenio of the Kavli Institute of Cosmology. at the University of Cambridge, a member of the team behind the discovery said in a statement.
The results are part of the JWST Advanced Deep Extragalactic Survey (JADES) and are known as JADES-GS-z14-0 and JADES-GS-z14-1, with the former being slightly more distant than the latter.
The team was able to perform a spectroscopic examination of the galaxies, refracting their light into a rainbow. Using this rainbow, the researchers were able to find 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 is not all. Due to the expansion of the universe, the light is red-shifted. This is similar to the Doppler effect, which changes the pitch of an ambulance siren as the vehicle approaches or retreats. In the case of these galaxies, their light is stretched to extreme wavelengths.
“We see additional emission from hydrogen and possibly even oxygen atoms, as is common in star-forming galaxies, but here shifted to an unprecedented wavelength,” said Jakob Helton, a graduate student at the University of Arizona and lead author of one of the studies. of the papers describing the discovery.
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 own silent galaxy. Before JWST, astronomers didn’t expect galaxies to grow big, bright, and massive very quickly, but galaxies like this suggest that’s certainly one way they can grow.
“JADES-GS-z14-0 now becomes the archetype of this phenomenon,” says Dr. Stefano Carniani of the Scuola Normale Superiore in Pisa, lead author of 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 significantly closer to the Big Bang could soon be found.
“We could have detected this galaxy even though it was ten times fainter, which means we could have seen other examples even earlier in the universe – probably 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.”
The papers related to the discovery are awaiting peer review but have been posted on arXiv. The Carniani paper confirmed the distance, the Helton paper is all about the galactic properties, and the Robertson paper provides insight into how such a galaxy could grow so big in such a short time.