Since the launch of the James Webb Space Telescope in December 2021, astronomers and the public have been excited to see how powerful this new instrument is, and how it has been able to see some of the most distant galaxies ever observed. However, as an evolving science, some of these were early results controversial Astronomers work to see how accurate the data is, due to issues such as instrument calibration.
Another way to verify the results is to look for supporting evidence from other instruments, such as recent work with the Atacama Large Millimeter/submillimeter Array, or ALMA, a group of ground-based telescopes located in Chile, which has confirmed the age of a very distant galaxy using detections of oxygen.
A group of researchers from Nagoya University and the Japan National Astronomical Observatory examined a galaxy called GHZ2, or GLASS-z12, which was first identified in JAMES WEBB GLASS SCANNING. To find out if the galaxy is really as old as it seems, the researchers used ALMA to perform a technique called spectroscopy, in which the light coming from a target is split into different wavelengths. This shows the wavelengths that are missing due to being absorbed by a particular element – in this case, oxygen.
The research looked at the oxygen emission line and confirmed its redshift, which indicates the shift of light from a distant target toward the red end of the spectrum due to the expansion of the universe. This allowed them to confirm that the galaxy GLASS-Z12 is very ancient, dating back 367 million years after the Big Bang.
said lead author Tom Bakx of Nagoya University statment. “It was a very exciting time to be an observational astronomer, and we could track the status of the observations that will test the JWST results in real time.”
This finding is supported by the fact that the galaxies Webb observed include some of the oldest known galaxies, showing just how powerful our instruments are now at looking at the earliest stages of the universe.
“These deep ALMA observations provide strong evidence for the existence of galaxies within the first hundreds of millions of years after the Big Bang, and confirm the surprising findings from Webb’s observations,” said Jorge Zavala of the National Astronomical Observatory of Japan. “JWST’s work is just beginning, but we are already adjusting our models of how galaxies formed in the early universe to match these observations. The combined power of Webb and the ALMA radio telescope array gives us the confidence to push our cosmic horizons closer to the dawn of the universe.”
Publication of the research in the journal Monthly Notices of the Royal Astronomical Society.
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