In a recent study submitted to MNRASa collaborative research team used the first data set from the James Webb Space Telescope (JWST) to discover a candidate galaxy, CEERS-93316, which formed about 250 million years after the Bing Bang, which also established a new redshift record of z = 16.7. This finding is extremely intriguing as it demonstrates the power of JWST, which only started returning its first set of data a few weeks ago. CEERS stands for Cosmic Evolution Early Release Science Survey, and was created specifically for imaging with JWST.
“The past few weeks have been surreal, watching all the records that have stood for a long time with Hubble being broken by JWST,” says Dr. Rebecca Bowler, Ernest Rutherford Fellow at the University of Manchester and co-author. on the study. “Finding az=16.7 candidate galaxy is an amazing feeling – it was not something we expected from the early data.”
This new study references a dozen previous studies that measured objects up to redshifts z ? 10 using a mixture of observations on the ground and with the Hubble Space Telescope and the Spitzer Space Telescope.
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“It’s amazing to have already found such a distant candidate galaxy with Webb given that this is only the first set of data,” says Dr Callum Donnan, PhD student at the University of Edinburgh and author principal of the study. “It is important to note that to be certain of the redshift, the galaxy will need follow-up observations by 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. Since CEERS-93316 is only 250 million years old, one of the goals of cosmologists is to find out what happens 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,” says Dr Bowler. “Observations of this galaxy push observations back to when we think the first galaxies in existence formed. We’ve already found more galaxies in the very early Universe than computer simulations predicted, so there are clearly a lot of open questions about how and when the first stars and galaxies formed.
Given this incredible discovery in the JWST’s first dataset, it’s fascinating to think about just what this back-in-universe space telescope can see, and if it can see the Big Bang itself.
“In principle, JWST can detect galaxies at redshifts greater than 20, less than 200 million years after the Big Bang,” says Bowler. “These galaxies will likely be extremely difficult to find, but the detection of CERRS 93316 gives us hope that they may exist. Watch this location!”
“The most distant observed phenomenon is the Cosmic Microwave Background (CMB) which is the ‘afterglow’ of the Big Bang,” says Donnan. “The light from the CMB originates about 400,000 years after the Big Bang and has been observed by various instruments over the years – including the Planck satellite which was launched in 2009. Webb won’t be able to see that far, but it is able to probe the early stages of galaxy formation.
Although both Donnan and Bowler have said no further sightings are planned for CEERS-93316, they hope there will be in the future.
Redshift is part of what is called the Doppler effect, which astronomers use to measure distances in the universe. A common example of the demonstration of the Doppler effect is the change in sound wave pitch when a loud object travels towards you and then away from you, often by an ambulance or other first aid vehicle. The sound waves when the object is moving towards you are called blueshift, while the reverse is called redshift. This new study setting a new redshift record means scientists have measured the most distant object in the universe to date.
As always, keep doing science and keep looking up!