Astronomers have made a significant discovery, finding an ancient barred spiral galaxy that existed 11 billion years ago, just 3 billion years after the Big Bang. This discovery is remarkable as it challenges the current understanding of galaxy formation and evolution. Scientists have previously thought that barred spiral galaxies, like our own Milky Way, only started to appear when the Universe was around half its current age.
The galaxy, named G09 83808, was initially mistaken for a quasar due to the high amount of light it was emitting. However, closer examination using the Atacama Large Millimeter/submillimeter Array (ALMA) revealed that it was an ancient barred spiral galaxy. This discovery was unexpected, as these types of galaxies were thought to take a long time to form and evolve.
Barred spiral galaxies are characterized by a central bar-shaped structure made up of stars. Their distinct shape is believed to be a later-stage development in a galaxy’s life, which starts as a spiral and then develops a bar over time. Until now, it was believed that such galaxies only started to appear when the Universe was around half its current age.
The discovery of G09 83808 challenges this belief. The galaxy doesn’t just have a bar structure, but it also has two spiral arms emanating from the bar, which rotate around the galaxy’s center. The presence of these arms indicates that the galaxy was already well-structured at such an early stage in the Universe’s history, which is surprising to astronomers.
The team of researchers used the ALMA telescope in Chile to observe the galaxy, due to its ability to detect light from dust clouds in distant galaxies, which can be heated by star-forming regions. ALMA’s high sensitivity and resolution allowed the astronomers to see the detailed structure of G09 83808, even though it is so far away.
The discovery of this ancient barred spiral galaxy has important implications for our understanding of galaxy formation and evolution. It suggests that the processes leading to the formation of these galaxies may have started much earlier than previously thought. This raises many questions about what conditions were like in the early Universe and how these galaxies could have formed so quickly.
The team plans to continue to explore this galaxy and others like it, to learn more about how galaxies form and evolve. Future observations with telescopes like the James Webb Space Telescope, set to launch in 2021, will further help astronomers to unravel the mysteries of galaxy formation and evolution.
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