James Webb Finds 9-Billion-Year-Old Nuclear Disc in CEERS-4031, Pushing Back Early Galaxy Maturity
Updated
Updated · Earth.com · Jul 21
James Webb Finds 9-Billion-Year-Old Nuclear Disc in CEERS-4031, Pushing Back Early Galaxy Maturity
1 articles · Updated · Earth.com · Jul 21
Summary
CEERS-4031 already hosted a dense, fast-spinning nuclear disc of young stars when the universe was about 4.5 billion years old, making it the most distant such structure yet detected.
James Webb images show the Milky Way-sized galaxy had an orderly central disc a few thousand light-years across, evidence that some galaxies settled and built mature cores far earlier than standard models expected.
A 17,000-light-year stellar bar appears to be driving gas inward to form the disc, and researchers also found possible nuclear spiral arms and a smaller inner bar that may help feed the galaxy’s supermassive black hole.
The team said the disc’s large size and local-like structure suggest bar-driven evolution in the early universe could proceed briskly rather than over the billions of years usually associated with slower secular growth.
Published in Monthly Notices of the Royal Astronomical Society, the finding adds direct evidence that bars were already reshaping galaxies during Cosmic Noon, with larger future observatories expected to uncover smaller early discs.