Astronomers using the NASA/ESA/CSA James Webb Space Telescope discovered a very ancient grand design spiral galaxy that existed just a billion years after the Big Bang. Named Zhúlóng (Torch Dragon), this galaxy is the most distant bulging disc galaxy candidate for which spiral arms have been known to date.
This image of Zhúlóng, the furthest spiral galaxy discovered to date, shows its very well-defined spiral arm, old bulge in the middle, and a large star-forming disc resembling the structure of the Milky Way. Image credits: NASA/CSA/ESA/M. Xiao, University of Geneva/G. Brammer, Niels Bohr Institute/Dawn JWST Archive.
Large spiral galaxies like our Milky Way are expected to take billions of years to form.
For the first billion years of universe history, galaxies are considered small, chaotic and irregular.
However, Webb is beginning to reveal very different photos.
Telescope deep infrared imaging reveals surprisingly large and well-structured galaxies much earlier than previously expected.
Among these new findings is Zhúlóng, the most distant spiral galaxy candidate ever identified, seen at a redshift of 5.2.
Despite this early period, galaxies exhibit surprisingly mature structures. Old bulge in the middle, large star-forming discs, spiral arms – a feature usually found in nearby galaxies.
“What stands out for Zhúlóng is both how similar it is to the Milky Way, its shape, size and star mass,” says Dr. Mengyuan Xiao, a postdoctoral researcher at Unige.
“The disc spans over 60,000 light years, comparable to our own galaxy, and the star contains over 100 billion solar masses.”
“This makes it one of the most persuasive Milky Way analogs discovered at such an early age, raising new questions about how a large, ordered spiral galaxy will form right after the Big Bang.”
The Zhúlóng Galaxy was discovered as part of a panoramic investigation.
“The findings highlight the possibility of purely parallel programs to reveal rare, distant objects that stress-test galaxy formation models,” says Dr. Christina Williams, a No-Arab astronomer and lead researcher of the Panorama Program.
Spiral structures were previously thought to take billions of years, but large galaxies were not expected to exist much later in the universe.
“The discovery shows that Webb is fundamentally changing the way we see the universe in its early days,” says Professor Pascal Oesch, an astronomer at Unige and a co-researcher of the Panorama Program.
a paper The discovery was published in the journal today Astronomy and Astrophysics.
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Mengyuan Xiao et al. 2025. Panorama: Discovery of a super gentle grand design spiral galaxy from z to 5.2. A&A 696, A156; doi:10.1051/0004-6361/202453487
Source: www.sci.news
