Astronomers have discovered pond-like ripples throughout the gas disks of ancient galaxies.
What causes the ripples? And what do the ripples tell us about the formation and evolution of distant galaxies? And whatever happens, does it explain the effects of galaxies and their main job, the stars? What influence did it have on its formation?
This discovery concerns the oldest known spiral galaxy. It is over 12 billion years old and is called BRI 1335-0417. As the oldest known spiral, it holds an important place in studying how galaxies form and evolve.
Scientists say the ripples in BRI 1335-0417’s disk reveal the galaxy’s growth pattern. Observations show the disk moving vertically, like ripples on a pond. This is the first time this phenomenon has been observed, and the ripples could help explain star formation within galaxies.
This observation is Royal Astronomical Society Monthly Notices. The title of the study is “Disk bending waves detected in a barred spiral galaxy at redshift 4.4.The lead author is Dr. Takafumi Tsukui, a postdoctoral fellow at the Australian National University’s Research Institute of Astronomy and Astrophysics (RSAA).
BRI 1335-0417 is known for its fast star formation rate. It forms far more stars than modern galaxies like the Milky Way. Some measurements show that stars form hundreds of times faster than our galaxy. Somehow, gas is transported and turned into stars more efficiently than in other galaxies.
The observations that revealed the ripples were made with ALMA, the Atacama Large Millimeter/Submillimeter Array. ALMA is particularly good at observing gas and dust, which helps us observe ripples. Researchers say the ripples are evidence of some kind of external influence, such as an interaction with another galaxy or perhaps incoming gas. Both of these effects can cause rapid star formation and may help explain why BRI 1335-0417 forms stars so quickly.
But ALMA discovered more than just ripples. Evidence of a stick in the center was also found.
The bars of spiral galaxies can promote star formation by channeling gas from the arms into the central region of the galaxy, fueling star birth there.The same process can also be explained active galactic nucleus.
“A rod bridging the previously identified two-armed spiral with a radius of 3.3 +/- 0.2 kiloparsecs in length is evident in both regions. [C-II] and [far infrared] “This image shows that streaming gas toward the core drives the galaxy’s rapid evolution,” the researchers wrote in their paper.
Spiral galaxy bars are normal. A study showed We found that more than a quarter of all spiral galaxies have bars. Both the Milky Way and our closest neighbor, the Andromeda galaxy, are barred spirals. This bar is temporary and may decay over time, allowing the barred spiral galaxy to transform into a simpler spiral galaxy. The rod may only have a lifespan of about 2 billion years. They can be periodic, forming and collapsing, which helps explain why we find so many of them.
Some established astronomical ideas say that bar formation is the final step in galaxy evolution.
“Bar formation may be the last important act in the evolution of spiral galaxies,” said Kartik Sheth of the Spitzer Science Center, commenting on the 2008 study.
“Galaxies are thought to build themselves through mergers with other galaxies. Once settled, the only other dramatic way in which galaxies evolve is through bar action.”
But astronomers have never discovered bars in galaxies this early in the universe.
This suggests that the mechanisms by which the bars form are different. “The bar identified by [C-II] and [far infrared] Images of gas-rich disk galaxies suggest new perspectives on early bar formation in high-redshift gas-rich galaxies. In other words, the gravitationally unstable, gas-rich disk creates the gaseous rods that form stars, rather than the stellar rods that emerge from pre-existing stars. “It is a stellar disk,” the authors write.
“This may explain the common bar-like structures seen in FIR images of high-redshift submillimeter galaxies,” the authors explain.
Finding these ripples and bars in this ancient galaxy forces a rethink. The gas disks of galaxies like this are usually stable, so the ripples indicate that something has happened to the disk recently.
It’s unclear whether it’s an interaction with another galaxy or a giant cloud of gas. However, this conclusion seems obvious to the author. “It is natural to think that such interactions would also activate advanced star-forming activity,” they write.
Astronomers believe that galaxies form and evolve through mergers with other galaxies and giant gas clouds. These findings do not challenge this idea. But observing the striking ripples gives researchers a new window into how it works.
This article was first published today’s universe.read Original work.