Yang Xiangyi, assistant professor at the Institute of Astronomy, Tsinghua University, and an international team have used advanced computer simulations to confirm that astronomers have observed two huge bubbles in the Milky Way—the eRosita bubble and the Fermi bubble in the past, and they are actually 2.6 million years old. The eruption of energy from the supermassive black hole in the center of the former Milky Way indicates that although the black hole of the Milky Way is currently in a dormant period, it is definitely not tame, and it was indeed actively erupting millions of years ago.
Yang Xiangyi said that the high-energy particles and shock waves that formed these two sets of huge bubbles are still expanding outward at an ultra-high speed of 1,500 kilometers per second, and are gradually coming towards our solar system. Fortunately, it should take several million years. Only then will we reach the earth, and there will be no crisis like the movie “Don’t Look Up”, so don’t worry too much for the time being.
A multinational research team composed of astronomers from Tsinghua University, the University of Michigan, and the University of Wisconsin has uncovered the mystery of the origin of the Milky Way’s giant bubble. This major astronomical research achievement was also published in the top international journal Nature Astronomy this month.
Yang Xiangyi said that in 2010, international astronomers used the Fermi Gamma-ray Telescope to discover that there are two huge bubbles in the center of the Milky Way, which are symmetrical up and down with the disk of the Milky Way as the center, and named Fermi bubbles. At that time, the astronomical community was arguing about the formation of the Fermi bubble. One group believed that it was caused by the energy eruption of the black hole, and the other group claimed that it was the galactic wind generated by the supernova explosion.
It wasn’t until 2019 that astronomers launched another extended ROentgen Survey with an Imaging Telescope Array, and soon observed two bubbles similar in shape to Fermi bubbles, but larger and symmetrical. Bubble, called Yirosita Bubble.
Therefore, Yang Xiangyi, who has been studying black holes for a long time, cooperated with an international team to input the latest observation data of the Erosita telescope into the computer for hydrodynamic simulation. Caused by the same black hole jet event, the inner circle of the ejected bubble is gamma rays emitted by high-energy particles ejected by the black hole, and the outer circle is X-rays released by gas shock waves.
Yang Xiangyi explained that when the black hole at the center of the Milky Way absorbs matter of 10,000 to 100,000 times the mass of the sun, only a small part is actually eaten into the area where even light cannot escape, and most of the matter will still be spit out and interact with the magnetic field. Jets outward at close to the speed of light, and push the gas out of the Milky Way, forming huge bubbles. And because the disk of the Milky Way is full of stars, which creates resistance, it is like tying a belt in the middle of the bigger and bigger bubbles, so that two mushroom-shaped bubbles that are symmetrical up and down can be formed.
“This study gives us a better understanding of how supermassive black holes in the universe evolve and interact with other galaxies,” said Mateusz Ruszkowski, a professor at the University of Michigan who collaborated on the research. What effects do bubbles of enormous energy have on the evolution of galaxies.