Now that JWST has discovered these strong galaxy candidates at vast distances, the next questions are how much farther back in time JWST can see and whether it will be enough to discover the very first galaxies that existed, perhaps just 100 million years after the Big Bang. "Should follow up spectroscopy validate, our universe was already aglow with galaxies less than 300 million years after the Big Bang," Finkelstein's team wrote in their paper. James Webb Space Telescope discovers candidates for most distant galaxies yet
#EVEN REMOTELY DEFINITION FULL#
With the James Webb Space Telescope in full operations, scientists look to reveal the earliest galaxies
Dazzling James Webb Space Telescope image prompts science scramble Contrary to some expectations, the rate of star formation might decline gradually the farther back in time we look, rather than there being a sharp drop-off beyond redshift 11. The amount of ultraviolet light (redshifted into the longer wavelengths of infrared, making it visible to JWST), coupled with the abundance of high-redshift galaxies that it is finding so early in its mission, suggests that galaxies were plentiful in the earliest history of the universe.
Still, the new detections represent generations of galaxies that followed closely after, and that scientists see in the early stages of development. Scientists haven't yet identified any of the very first galaxies in the universe, which may lie at redshift 25 or beyond. Astronomers estimate that the cosmic babies are less than 100 million years old, and possibly as young as 20 million years. These galaxies span only 1,000 or so light-years across and contain just tens of millions of stars modern galaxies can host hundreds of billions of stars. The plethora of high-redshift galaxies being discovered can be considered cosmic babies. Donnan's team concluded that there is more than enough ultraviolet radiation being produced by the stars in these early galaxies to ionize the universe. The value is strongly tied to star formation, because the more hot young stars are being formed in a galaxy, the more ultraviolet light it emits. This function is an average of the amount of ultraviolet light associated with galaxies at any particular epoch. In their paper, Donnan's team calculate the "galaxy ultraviolet luminosity function" between redshifts of 8 and 15. Indeed, all the distant galaxy candidates display evidence for strong ultraviolet light emission, enough to possibly settle the debate as to what ionized the hydrogen gas in the universe, bringing an end to the so-called " Cosmic Dark Ages." Over the years, astronomers have suggested causes ranging from radiation from the first stars and galaxies to outflows of radiation from the first supermassive black holes. If a closer look at the archived data does reveal the galaxy, then Maisie's Galaxy must produce very strong ultraviolet light from a powerful burst of star formation for Hubble to have spotted it. The astronomers found that this galaxy may have also been seen by the Hubble Space Telescope, but not recognized at that time. Meanwhile, using the same observations from CEERS, another team led by Steven Finkelstein of the University of Texas at Austin discovered a galaxy with a redshift of 14.3, placing it 280 million years after the Big Bang, which the researchers have named "Maisie's Galaxy" after Finkelstein's daughter. The team also found five other galaxies with a redshift greater than 12, all of which exceed the redshift record set by JWST's predecessor and now colleague, the Hubble Space Telescope.
student Callum Donnan of the University of Edinburgh, found a candidate galaxy at a redshift of 16.7, which equates to just 250 million years after the Big Bang. JWST's Near-Infrared Spectrograph (NIRSpec) joins in observations of six of those patches, while the space telescope's Mid-Infrared Instrument (MIRI) studies four. These images are part of the Cosmic Evolution Early Release Science (CEERS) survey, which consists of images of 10 different patches of sky by JWST's Near-Infrared Camera (NIRCam). Two other papers report finding high-redshift galaxies in patches of the sky where JWST has simply taken deep exposures, without resorting to gravitational lensing. Because of cosmic expansion, today these galaxies would be over 35 billion light-years away from us. If validated, these galaxies would be, by far, the most distant ever detected. Astronomers led by Haojing Yan of the University of Missouri-Columbia used the gravitational lens created by the galaxy cluster SMACS J0723 to detect 88 candidate galaxies beyond a redshift of 11, including a handful estimated to be at a redshift of 20. The galaxies have been detected using different techniques.
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