" China Sky Eye " detects the largest atomic gas system discovered so far in the universe! , an atomic gas system with a scale of about 2 million light years, is located in the famous dense galaxy group " Stephen Five-Galaxy ", which is 20 times larger than Milky Way . At 23:00 on October 19, the international academic journal Nature published this research result.
FAST gas distribution in the celestial area around the famous dense galaxy group "Stephen Five-layer Galaxy" detected by
FAST (displayed with red halo; the thinner halo means the lower the density of the gas column). The background in the figure is a color optical image obtained with an optical telescope. Stephen's Five-fold Galaxy is located in the middle of the image. The embedded image is the infrared band color diagram recently released by the Webb Space Telescope: blue and white light represent the stellar radiation in the near-infrared band, and orange and red light represent the gas and dust radiation in the mid-infrared band (Picture source: NASA, ESA, CSA, STScI).
A very important study in astrophysics is to observe gases in the universe. The origin of all celestial bodies in the universe is inseparable from atomic gas. For example, the main evolutionary process of galaxies is to continuously absorb atomic gas from the universe and then convert it into stars.
Through the radio astronomical band, astronomers can make direct observations of atomic gases in the universe. As the largest single-aperture radio telescope with the highest caliber and highest sensitivity in the world today, the "China Sky Eye" FAST can detect dark and weak radiation emitted by extremely thin diffuse atomic gases far away from the center of the galaxy. This opens a new window for studying the origins of celestial bodies in the universe.
Recently, an international team led by Xu Cong, a researcher at the National Observatory of the Chinese Academy of Sciences, used FAST to image and observe the famous dense galaxy group "Stephen Five-layer Galaxy" and the hydrogen atom gas in the surrounding sky. Thanks to the unprecedented extreme dark and weak celestial detection capabilities brought by FAST's ultra-high sensitivity, the team discovered a huge atomic gas system with a scale of about 2 million light years, 20 times larger than our Milky Way.
"This is the largest atomic gas system detected in the universe so far." Xu Cong told reporters that since he was discovered by French astronomer Stephen in 1877, the "Stephen Five-layer Galaxy" is the most popular galaxy group , and has also become one of the five targets that the Webb Space Telescope observes and displays to the public for the first time. "The formation of these gas structures is likely to be related to the history of intergalactic interactions at the early stage of the formation of the Stephen Five-layer Galaxy, and may have existed for about a billion years."
This latest discovery reveals the existence of large-scale low-density atomic gas structures in the peripheral space far from the center of the galaxy cluster, and also challenges the evolution of galaxies and their gases in the universe. Existing theories are difficult to explain why, for such a long time, these thin atomic gases have not been ionized by ultraviolet background radiation in the universe, and this observation from FAST predicts that there may be more such large-scale low-density atomic gas structures in the universe.
Author: Xu Qimin
