Astronomers have discovered a barred spiral galaxy just 2 billion years after the Big Bang, challenging current theories on how galaxies form and evolve. The finding adds to growing evidence that galaxies formed more quickly than previously thought.
The discovery of this ancient barred spiral, dubbed J0107a, has significant implications for our understanding of galaxy evolution. Barred spirals are characterized by a thick central structure that forms naturally from the stars’ orbits. This type of galaxy is considered an evolutionary step beyond traditional spiral galaxies.
The new data, published in Nature, reveal J0107a as it was 11.1 billion years ago, with its bar appearing similar to those found in our Milky Way’s neighboring galaxies. The presence of gas and dust in the bar suggests that it has been around for about 1 billion years.
Further analysis shows that the galaxy is experiencing a stellar baby boom due to a massive influx of gas into the central regions. This phenomenon occurs because there was more gas available at earlier cosmic times, leading to an effect 10-100 times more intense than in local galaxies.
While J0107a is just one example, it pushes back the starting time when barred spirals began to form, directly confronting existing theories on galaxy evolution. The team proposes that bars formed spontaneously, developing naturally from a disk dominated by ordered rotation without external disturbance.
This discovery highlights the importance of ongoing observations using advanced telescopes like ALMA and Webb. Future findings will be crucial in rewriting the stories of galaxy formation and evolution, revealing more about how galaxies came to be as we see them today.
Source: https://skyandtelescope.org/astronomy-news/evolved-galactic-structure-in-early-universe