Astronomers are now discovering record-breaking distant galaxies by the dozen, sifting through the treasure trove of data now being collected by the James Webb Space Telescope (JWST or Webb). Many of them are galaxies that date back exactly 200 million years after the Big Bang.
before the launch of James Webb Space TelescopeThe most distant confirmed galaxy known was GN-Z11Which astronomers saw after about 420 million years big BangGiving it what astronomers call a red shift of 11.6. (Redshift tells how much light coming from the galaxy has been magnified as youthe universe expands, The higher the redshift, the further back in time we see a galaxy.)
just a week after release first science images From JWST, astronomers were reporting the detection of galaxies redshift 13, approximately 300 million years after the Big Bang. Now, a new wave of scientific results are breaking that record, with some astronomers reporting the detection of galaxies up to a redshift of 20. If true, we have been seeing these galaxies as they existed about 200 million years after the Big Bang.
It is too large if: At this stage, none of these redshift values are confirmed. Confirming the distances to these galaxies would require spectroscopic analysis, which splits the light from an object into what scientists call a spectrum. That analysis will come later. Nevertheless, it appears clear that the JWST is fully capable of detecting galaxies from this long-lost era.
Galaxies have been detected using various techniques. Astronomers led by Haojing Yan of the University of Missouri-Columbia used gravity lens formed by the galaxy cluster SMS J0723 88 candidate galaxies to be detected beyond a redshift of 11, some of which are estimated to be at a redshift of 20. If validated, these galaxies would be the most distant ones ever discovered. Due to cosmic expansion, these galaxies would be 35 billion light years away from us today.
Two other papers report finding high-redshift galaxies in patches of sky where JWST has taken only deep exposures without resorting to gravitational lensing. These images are part of the Cosmic Evolution Early Release Science (CEERS) survey, which includes images of 10 different patches of sky by JWST’s Near-Infrared Camera (NIRCAM). JWST’s near-infrared spectrograph (NIRSPC) joins in observing six of those patches, while the Space Telescope’s Mid-Infrared Instrument (MIRI) studies four.
PHD. A team of astronomers led by University of Edinburgh student Callum Donnan found a candidate galaxy at a redshift of 16.7, the equivalent of just 250 million years after the Big Bang. The team also found five other galaxies with more than 12 redshifts, all of which exceed the redshift record set by JWST’s predecessor and now collaborator. Hubble Space Telescope,
Meanwhile, using similar 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, placed 280 million years after the Big Bang, which the researchers called. Named “Maisie’s Galaxy”. After Finkelstein’s daughter. Astronomers found that this galaxy can also be seen by the Hubble Space Telescope, but it was not identified at the time. If a closer look at the archived data reveals the Milky Way, Massey’s Galaxy must have been producing very strong ultraviolet light from a powerful burst of star formation for Hubble to see.
In fact, all distant galaxy candidates display evidence for strong ultraviolet light emission, which is probably enough to settle the debate that hydrogen gas has been ionized in the universe, leading to the end of the so-called “cosmic dark ageFor years, astronomers have suggested causes ranging from radiation from earlier stars and galaxies to radiation outflows from the first supermassive black holes.
In their paper, Donnan’s team calculates a “galaxy ultraviolet brightness function” between a redshift of 8 and 15. This function averages the amount of ultraviolet light associated with galaxies at a particular epoch. Mann is strongly linked to star formation, because the more hot young stars are forming in the galaxy, the more ultraviolet light is emitted. Donnan’s team concluded that more than enough ultraviolet radiation is being produced by the stars in these early galaxies to ionize the universe.
The plethora of high-redshift galaxies being discovered can be considered cosmic babies. These galaxies span only 1,000 or so light-years and contain only tens of millions of stars; Modern galaxies can host hundreds of billions of stars. Astronomers estimate the cosmic children to be less than 100 million years old, and possibly as young as 20 million years.
Scientists have yet to identify any of the first galaxies in the universe that could be located at a redshift of 25 or beyond. Nevertheless, the new discoveries represent generations of galaxies that closely followed, and scientists see in the early stages of evolution.
The amount of ultraviolet light (redistributed to longer wavelengths of infrared, making it visible to JWST), along with the abundance of high-redshift galaxies it has been searching for so early in its mission, suggests that galaxies were plentiful in their early history. The universe was in quantity. Contrary to some expectations, instead of a sharp decline beyond redshift 11, the rate of star formation may gradually decrease as we observe.
“Follow up spectroscopy should validate [these redshifts], [it means that] Less than 300 million years after the Big Bang, our universe was already brimming with galaxies,” Finkelstein’s team wrote in their paper.
Now that JWST has discovered these strong galaxy candidates over vast distances, the next question is how long ago JWST can see and whether it will be enough to discover the earliest galaxies, perhaps just after the Big Bang. 100 million years later. , Such a discovery would require a huge dose of luck, as it would rely on incidental gravitational lensing to see the elemental galaxies.