Our understanding of disk galaxy structure has long been a topic of debate among astronomers. Recent data from NASA’s James Webb Space Telescope has shed new light on this mystery, revealing that many disk galaxies have two distinct disks: a thick outer disk and an embedded thin inner disk.
Researchers analyzed archival data from 111 edge-on disk galaxies, spanning up to 11 billion years ago, and found that high-mass galaxies transitioned to double-disk structures around 8 billion years ago, while low-mass galaxies formed their embedded thin disks later on, about 4 billion years ago. This discovery suggests that a turbulent gas disk in the early universe sparks intense star formation, forming a thick stellar disk.
To explain this process, scientists considered the motion of galaxies’ gas disks and found that it aligns with one of three major hypotheses: the “turbulent gas disk” scenario. According to this scenario, as stars form, they stabilize the gas disk, which becomes less turbulent and thinner.
This new understanding has significant implications for our own galaxy, the Milky Way. The team notes that the transition period from a thick disk to a thick and thin disk roughly coincides with the formation of the Milky Way’s thin disk.
The James Webb Space Telescope is allowing astronomers to observe smaller and fainter galaxies at early times with unprecedented clarity. This study provides valuable insights into galaxy formation history, and future research plans include incorporating additional data points to refine our understanding of disk formation.
This groundbreaking discovery highlights the importance of NASA’s James Webb Space Telescope in solving mysteries about our universe and its place in it.
Source: https://science.nasa.gov/missions/webb/nasas-webb-digs-into-structural-origins-of-disk-galaxies