A new study led by a joint team from Nagoya University and the National Astronomical Observatory of Japan measured the cosmic age of a very distant galaxy. The team used the ALMA radio telescope array to detect a radio signal that was present for about 97% of the age of the universe. This discovery confirms the existence of galaxies in the very early universe found by the James Webb Space Telescope. Study published Monthly Notices of the Royal Astronomical Society.

The galaxy, designated GHZ2/GLASS-z12, was first identified during the JWST GLASS survey, which observed the distant Universe and large galaxy clusters. These observations consist of multiple images using different broadband color filters similar to the individual RGB colors in the camera. In distant galaxies, light takes so long to reach us that the expansion of the universe has shifted that light’s color toward the red end of the visible light spectrum, known as a redshift. Therefore, GHZ2/GLASS-z12’s red color helped the researchers identify it as one of the most attractive candidates for a distant galaxy they’ve observed.

In the first few weeks of observations by the James Webb Space Telescope (JWST), so many bright distant galaxies were identified that it challenged our basic understanding of the formation of the earliest galaxies. However, these red colors only indicate a distant galaxy and may instead be a very dusty galaxy that appears to be a more distant object. Only direct observations of spectral lines—lines found in a galaxy’s light spectrum and used to identify elements present—can reliably confirm the true distance to these galaxies.

Shortly after the discovery of these early candidate galaxies, two young researchers from Nagoya University and the National Astronomical Observatory of Japan used the forty ALMA radio telescope in Chile to find a spectral line to confirm the true age of the galaxies. .

ALMA pointed to GHZ2/GLASS-z12 to find an oxygen-related emission line at the expected frequency suggested by the JWST observations. Oxygen is often a common element in distant galaxies due to its relatively short formation time, so the team decided to look for the oxygen emission line to increase the chances of detection.

By combining signals from each of its 12-metre telescopes, ALMA was able to detect an emission line close to the galaxy’s location. The observed redshift of the line shows that we see the galaxy as it was just 367 million years after the Big Bang.

“The first images from the James Webb Space Telescope revealed so many ancient galaxies that we felt compelled to confirm their results with the best observatory on Earth,” said lead author Tom Bax of the University of Nagoya. “It was a very exciting time to be an observing astronomer and we were able to monitor the status of observations that would validate the JWST results in real time.”

“We were initially concerned about the small difference in position between the detected oxygen emission line and the galaxy seen by Webb,” says author Tom Bax, “but we conducted detailed observational tests to confirm that this is indeed a solid detection and very reliable.” difficult to explain.” in another interpretation.”

Co-author Jorge Zavala, of the National Astronomical Observatory of Japan, adds: “The bright-line emission shows that this galaxy is rapidly enriching its gas reservoirs with elements heavier than hydrogen and helium. This gives us some clues about the formation, evolution, and life of first-generation stars. “The small distance we see between stellar emission may also indicate that these early galaxies suffered from violent explosions that blew gas from the center of the galaxy to the region around the galaxy and even beyond.”

“These deep ALMA observations provide strong evidence for the existence of galaxies in the first few hundred million years after the Big Bang and confirm the surprising results of Webb’s observations. The work of JWST has just begun, but we already have our models of galaxy formation in the early universe to fit these observations.” “The combined power of the Webb and ALMA radio telescope array gives us the confidence to bring our cosmic horizon closer to the birth of the universe.”