There are now very few phenomena in space that are completely unknown to us, but in 2019, astronomers discovered a very large and yet unexplained object called an “Odd Radio Ring (ORC).” Now they have a reasonable explanation, with new analysis showing that these faintly glowing rings are shock waves caused by huge winds blowing from the centers of starburst galaxies.
Odd radio circles (ORCs) are quite bright at radio wavelengths, but are not visible at visible, infrared or Discovered for the first time in data from the Array of Radio Telescopes (ASKAP).
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More strange radio wave rings will begin to be discovered in 2022. Astronomers have confirmed that these objects are quite large, spanning millions of light-years across, and centered on certain galaxies. The latest research will be related to strange radio wave rings and “starburst galaxies” Get in touch.
When two large galaxies collide, they trigger a merger, pushing all the gas into a tiny area, resulting in massive star formation, called a starburst galaxy. However, star birth is accompanied by star death. After a period of time, starburst galaxies will produce a large number of supernovae at the same time. Because many stars explode one after another at the same time, the gas they eject is accelerated into strong winds and flows out of the galaxy at a speed of 2,000 kilometers per second.
Strange radio-wave rings may appear late in the process.
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To get answers, researchers investigated a galaxy with strange radio waves, and sure enough, they discovered that there seemed to be a large amount of bright, hot, compressed gas at the center of the galaxy. According to data, the star age of this galaxy is about 6 billion years old, and the crazy starburst period ended about 1 billion years ago.
▲Simulation of powerful galactic winds driven by starburst galaxies.
Then the results of simulating the properties of galaxies, stars and the strange radio rings around them showed that the outward flowing wind stopped blowing for about 200 million years, and then a shock wave spread, pushing the hotter gas farther to form a radio ring, and another The shock wave propagates in the opposite direction, pushing the cooler gas back into the galaxy. The entire process takes about 750 million years.
For the above process to be completed successfully, the galaxy must blow out strong winds to rapidly eject large amounts of material, indicating that the strange radio wave ring does originate from some kind of outflowing galactic wind.
Scientists say that we can learn a lot from strange radio wave rings and better understand the evolution of galaxies, such as whether all massive galaxies will go through the ORC stage.
new paperPublished in the journal Nature.
(Source of first picture:University of California, San Diego）
