An international team led by the University of Geneva (UNIGE) has discovered the most distant spiral galaxy known to date. This flat -shaped disk system only existed a billion years after the Big Bang, very early on on the scale of the universe.
Large spiral galaxies and the Milky Way should take several billion years to form. However, the James Webb space telescope (JWST) is starting to reveal other scenarios.
Among these discoveries is a candidate spiral galaxy – a galaxy whose confirmation is still to come – which would be the most distant ever identified. It was dated just a billion years after the Big Bang.
Despite this early era, the galaxy has an surprisingly mature structure: an old central bulb, a large, stars and spiral arms disc, characteristics generally observed in galaxies much more distant from Big Bang.
Dragon rouge
“We have baptized this Zhúlóng galaxy, which means ‘Torch dragon’ in Chinese mythology. In the myth, Zhúlóng is a powerful red solar dragon that creates day and night by opening and closing their eyes, symbolizing the light and cosmic time,” explains Mengyuan Xiao, postdoctoral researcher in the department of unige main author of the study.
“Zhúlóng is distinguished by its resemblance to the Milky Way, both by its shape and by its size and stellar mass,” added the scientist, quoted Wednesday in a UNIGE press release. Its disc extends over more than 60,000 light years, which is comparable to our own galaxy, and contains more than 100 billion stars’ solar masses.
This configuration makes it one of the analogues of the most convincing Milky Way ever discovered in such an early time. It raises new questions about how spiral, massive and well -ordered galaxies were able to train so shortly after the Big Bang.
A story to rewrite
It was previously believed that spiral structures put billions of years to develop, and that massive galaxies should not exist until much later in the universe, because they are generally formed after the fusion of smaller galaxies.
According to Pascal Oesch, associate professor in the Unige’s astronomy department, “this discovery shows that JWST fundamentally changes our vision of the primitive universe”. Future observations of JWST and ATACAMA Large Millimeter Array (Alma) will confirm its properties and learn more about the history of its training.
Astronomers expect to find other galaxies of this type as new JWST surveys. What better understand the complex processes that shaped galaxies at the start of the universe. These works are published in the magazine Astronomy & Astrophysics.
This article was published automatically. Source: ATS
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