With the advent of modern telescopes and astronomical observations, astronomers have been able to identify many distant galaxies. These were some of the first galaxy to form the universe that began to fall back on us as the universe expanded. In fact, as the distance increases, the galaxy seems to move away from us at an instant. Interestingly, we can estimate how fast the galaxy moves, too, when it is constructed based on how its “reddish” emissions appear. This is similar to an event called the “Doppler effect,” in which objects moving away from the viewer emit light that appears to be converted to long wavelengths (hence the term “redshift”) on the viewer.
The Atacama Large Millimeter / submillimeter Array (ALMA) telescope located in the middle of the Atacama Desert in Chile is especially well-suited for observing such variations in galaxy emissions. Recently, a team of international researchers including Professor Akio Inoue and graduate student Tsuyoshi Tokuoka of Waseda University, Japan, Dr. Takuya Hashimoto at Tsukuba University, Japan, Professor Richard S. Ellis at University College London, and Drs. Nicolas Laporte, a researcher at the University of Cambridge, UK, has observed a modified version of the long galaxy, MACS1149-JD1 (hereafter JD1), which has led to some interesting conclusions. “Apart from discovering the high-redshift, that is, the farthest galaxies, studying its internal gases and galaxies provides the impetus for understanding the process of galaxy formation in a very ancient place,” explains Ellis. The findings of their study were published in the Astrophysical Journal Letters.
The formation of the Galaxy begins with the accumulation of gas and continues with the formation of stars in that galaxy. Over time, the formation of the star progresses from the center to the outside, the galactic disk grows, and the galaxy acquires a certain shape. As star formation continues, new stars form on the rotating disk while old stars settle in the center. By studying the age of the astronomical objects and the movement of stars and gases in the galaxy, it is possible to determine the evolutionary stage the galaxy has reached.
Carrying out a series of observations over a two-month period, astronomers successfully measured the slightest difference in “redshift” from space to space within the galaxy and found that JD1 satisfied the galaxy’s orbital rule. Next, they likened the galaxy to a rotating disk and found that it reproduced what they had seen. The calculated rotational speed was about 30 miles [50 km] per second, compared with the rotational speed of the Milky Way disk at 120 miles per second. The team also measured the range of JD1 at only 3,000 light-years, much smaller than the Milky Way by 100,000 light-years wide.
The significance of their result is that JD1 is a very distant source and, therefore, an ancient source discovered with a rotating disk of gas and stars. Consistent with the same estimates of the closest systems in the research literature, this has allowed the team to explain the gradual development of orbiting galaxies over 95% of our cosmic history.
In addition, the weight of the galaxy’s orbit around the galaxy was the same as the weight of the galaxies previously measured from the galaxy’s signature signature, and it appeared significantly from that of the “mature” stars formed 300 million years ago. “This shows that the number of stars in JD1 formed during the cosmic era,” Hashimoto said.
“The JD1 rotation speed is slower than that found in galaxies in recent times with our Galaxy and it is possible that JD1 is in the early stages of making a rotating motion,” Inoue said. With the recently launched James Webb Space Telescope, astronomers now plan to identify the positions of younger and older galaxies in the galaxy to confirm and update their galaxy structure.
Source Journal Reference: Tsuyoshi Tokuoka, Akio K. Inoue, Takuya Hashimoto, Richard S. Ellis, Nicolas Laporte, Yuma Sugahara, Hiroshi Matsuo, Yoichi Tamura, Yoshinobu Fudamoto, Kana Moriwaki, Guido Roberts-Borsani, Ikkoh Shimizu, Satoshi Yamanaka, Naoki Yoshida, Erik Zackrisson, Wei Zheng. Possible Systematic Rotation in the Mature Stellar Population of a z = 9.1 Galaxy. The Astrophysical Journal Letters, 2022; 933 (1): L19 DOI: 10.3847/2041-8213/ac7447
