A team of researchers has used the James Webb Space Telescope (JWST) to observe distant edge-on galaxies, revealing a consistent trend in galaxy disk structures. The study analyzed 111 images of these galaxies, which allowed them to identify thin and thick disks.
The early universe had more single-thick-disk galaxies, while later epochs showed two-layered structures with thin disk components. This suggests that galaxies formed a thick disk first, followed by the formation of a thin disk within it. The study estimated the thin disk formation time for Milky Way-sized galaxies to be around 8 billion years ago.
The team examined not only stellar structure but also gas motion and star formation rates to support this scenario. They found that in the early universe, galactic disks were rich in gas and turbulent. As stellar disks developed, they helped stabilize the gas disks, leading to the formation of a thin disk inside the pre-developed thick stellar disks.
Larger galaxies can efficiently convert gas into stars, forming thin disks earlier. The JWST images provided valuable insights into galaxies that resemble the Milky Way’s early state, helping answer one of astronomy’s biggest questions: was our galaxy’s formation typical or unique?
The study bridges nearby and distant galaxies, refining our understanding of disk formation.
Source: https://www.eurekalert.org/news-releases/1089193