The James Webb Space Telescope has discovered a massive chain of 20 galaxies in the early universe, raising questions about the formation of the largest structures in the cosmos.
Astronomers using James Webb Space Telescope (JWST) data
have discovered a massive chain of at least 20 closely packed galaxies from the
early universe, and it could reveal insight into how the most massive
structures in the cosmos form.
JWST color-composed image of the Cosmic Vine. (Image credit:
arXiv) |
This megastructure — nicknamed the "Cosmic Vine"
in a study published Nov. 8 to the preprint database arXiv — swoops through
space in a bow shape, estimated to stretch more than 13 million light-years
long and about 650,000 light-years wide. (For comparison, our Milky Way galaxy
is about 100,000 light-years wide.) Astronomers detected the vast tendril of
gas and galaxies while studying James Webb Space Telescope observations of an
area called the Extended Groth Strip, located between the constellations Ursa
Major and Boötes.
The team was looking specifically for light from very early
galaxies, focusing on a property called redshift, a measure of how light
increases in wavelength as it travels vast distances through the expanding
universe. All of the galaxies observed in the Cosmic Vine showed a redshift of
roughly 3.44, meaning the light emitted by the objects traveled between 11
billion and 12 billion years — or for most of our 13.8 billion-year-old
universe's lifetime — before reaching JWST's lens.
The Cosmic Vine is "significantly larger" than
other galaxy groups observed so early in the universe's history, the team
wrote, adding it to a growing list of surprisingly huge structures in the early
universe discovered by JWST. According to the researchers, the Vine appears to
be on its way to becoming a galaxy cluster; these are the most massive
structures in the universe bound together by gravity, with masses typically
ranging from hundreds of billions to quadrillions of times the mass of the sun.
For now, the Cosmic Vine has an estimated mass of about 260
billion solar masses and is still growing — but its two largest galaxies may be
ready to call it quits. While studying the wavelengths of light emitted by the
two galaxies, the researchers found that star formation has all but stopped
there, designating them as "quiescent" or "quenched"
galaxies.
The authors pondered, what is "the culprit quenching
star formation" at such an early cosmic time? They noted that it is
unusual to find such large galaxies already running low on star-forming gas in
the ancient universe. One possibility is that both galaxies are the results of
recent galactic mergers, with cosmic collisions triggering wild bursts of star
formation that depleted most of the galaxies' available gas about half a
billion years before JWST's observations, the researchers wrote.
As with many recent JWST discoveries, the Cosmic Vine raises
more questions about the nature of our universe than it answers, and further
study is needed to solve the mysteries locked behind this ancient galactic
chain.
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