If confirmed, CEERS-93316 would be the most distant galaxy observed
The first dataset of James Webb Space Telescope (JWST) includes a candidate galaxy, CEERS-93316, which formed about 250 million years after the Big Bang. If the results of the survey, sent to the Monthly Notices of the Royal Astronomical Society, are confirmed, it would be the most distant galaxy observed, and confirmation of the potential of the new space telescope, which only makes scientific observations since one month.
The sighting, described in the arXiv repository, also includes an unprecedented redshift. The redshift is part of what is known as the Doppler effect, which astronomers use to measure distances in the universe. CEERS stands for Cosmic Evolution Early Release Science Survey and was created specifically for imaging with JWST.
“The last few weeks have been surreal, watching JWST break all of Hubble’s long-standing records,” said Dr Rebecca Bowler, Ernest Rutherford Fellow at the University of Manchester and co-author of the study. “Finding a candidate galaxy z=16.7 (redshift) is an amazing feeling, it was not something we expected from the early data.”
This new study builds on a dozen previous studies that have measured objects up to redshift z=10 using a combination of observations on the ground and with the Hubble Space Telescope and the Spitzer Space Telescope.
“It’s amazing to have found such a distant candidate galaxy with Webb given that this is only the first set of data.”says Callum Donnan, PhD student at the University of Edinburgh and lead author of the study, as quoted by Universe Today. “It’s important to note that to be sure of the redshift, the galaxy will need follow-up observations using spectroscopy. That’s why we call it a candidate galaxy.”
The study determined that CEERS-93316 cannot be a low-mass star or an unobstructed active galactic nucleus based on imaging data from NIRCam (Near Infrared Camera), which is JWST’s primary imager. Given that CEERS-93316 may only be 250 million years old, one of the goals of cosmologists is to learn what is happening in galaxies so young and so soon after the Big Bang.
“After the Big Bang, the Universe entered a period known as the Dark Ages, a period before stars were born,” he added. explains Dr. Bowler. “Observations of this galaxy push observations back to when we think the first galaxies to exist were forming. We have already found more galaxies in the early Universe than computer simulations predicted, so there are clearly many open questions.” on how and when the first stars and galaxies formed.
“In principle, JWST can detect galaxies with redshifts greater than 20, less than 200 million years after the Big Bang,” says Bowler. “These galaxies are likely to be extremely difficult to find, but the detection of CERRS 93316 gives us hope that they may exist.”
“The farthest observed phenomenon is the cosmic microwave background (CMB), which is the ‘glow’ of the Big Bang,” says Donnan. “The CMB light originates about 400,000 years after the Big Bang and has been observed by various instruments over the years, including the Planck satellite launched in 2009. Webb won’t be able to see until then, but it is able to probe the early stages of galaxy formation.
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