Entering ChinaThe reporter learned from Anhui Normal University that the research team of Professor Shu Xinwen of the School of Physics and Electronic Information of the university recently discovered the X-ray quasi-periodic oscillation signal sent by the mesomass black hole devouring the star, which is the first time that astrophysicists have discovered this kind of phenomenon, providing key evidence for the existence of intermediate-mass black holes in the universe. The research results were published in the top international journal Nature Astronomy on February 28, and the main collaborators also include researchers from the University of Science and Technology of China, Sun Yat-sen University, and Guangzhou University.
△The left image is an optical image of the galaxy where the intermediate-mass black hole is located, the middle image is an artistic image of the intermediate-mass black hole tearing apart the star, and the right image is the power density spectrum corresponding to the light-varying signal.
Although intermediate-mass black holes in the gap between the mass spectrum of black holes have been theoretically predicted to be the “seeds” of supermassive black hole evolution, there has been a lack of reliable observational evidence. How to find and detect this special population of intermediate-mass black holes is one of the most important frontier problems in physics and astronomy today. Combined with X-ray spectroscopy, the researchers estimated that the black hole has a mass of 9,900 to 16,000 times the mass of the sun, which belongs to the typical category of intermediate-mass black holes, and further estimated its spin to be between 0.26 and 0.36.
It is understood that when a star swims too close to the black hole, it will be torn apart by the strong tidal gravity generated by the black hole, and then swallowed by the black hole, while releasing a short period of intense electromagnetic radiation, which is called a black hole tidal tearing stellar event. The research team identified a special case of intermediate-mass black hole tidal disintegration stellar event candidate, and by analyzing relevant observational data, a quasi-periodic oscillation signal with a frequency of about 0.012 hertz was detected in its X-ray radiation, just like the “heartbeat” phenomenon of a black hole when it “preys” on stars, and its specific “heart rate” revealed the existence of this intermediate-mass black hole.
This discovery fills the key missing link in the history of the growth and evolution of the black hole family, which has positive significance for human understanding of how black holes are formed in the universe, and also lays a solid foundation for further exploration and research of intermediate-mass black holes in the future.
