MATHEMATICAL SCIENCES

Science published important progress in the computational astronomy team of Jiang Laboratory


On May 12, Science published an important discovery in the field of fast radio bursts, “Magnetic field reversal in the turbulent environment around a repeating fast radio burst.” Feng Yi, a research expert of Zhijiang Laboratory, is the co-first author of the paper, and Li Jing, chief scientist of computational astronomy of Zhijiang Laboratory, is the co-corresponding author of the paper.

Observations of fast radio bursts (FRBs), the most intense radio explosions in the universe that occur in milliseconds in the radio band, provide a new window into the mysteries of the universe. Since the first fast radio burst was discovered in 2007, it has quickly become the focus of astronomers. However, this field of research has long been plagued by too few samples, and research on its origin, evolution and other aspects once left astronomers at a loss, until “repetitive bursts” were observed.

As the name suggests, repetitive bursts are “fast radio bursts that repeat bursts.” Its emergence makes the study of fast radio bursts no longer a needle in a haystack, and astronomers can continuously detect specific targets to capture more burst data.

FRB 20190520B, the research object of Feng Yi et al.’s “Science” paper, is the world’s first continuous active repetitive storm discovered by China’s Tianyan FAST “Multi-science Target Simultaneous Sky Survey (CRAFTS)” project. Since its appearance on May 20, 2019, each monitoring of it has had one or more telescopes detect its eruption, which continues to be reliable.

Using the Parkes telescope in Australia and the Green Bank telescope in the United States, the research team led by Li Ji monitored FRB 20190520B for 17 months and measured its polarization properties, and found that its “Faraday rotation” changed dramatically.

“Faraday’s rotation conceals many features of the cosmic magnetic field environment and is essential for the study of radio astronomy.” Feng Yi explained that electromagnetic waves passing through the magnetized plasma will cause a change in the direction of vibration, which is called Faraday rotation. Fast radio bursts pass through plasma in the universe before reaching Earth, and Faraday rotates under the influence of magnetic fields, and the direction of vibration changes. And the value of Faraday’s rotation also indicates electron density and magnetic field strength. Therefore, the cosmic magnetic field environment through which the fast radio burst passes can be reversed by analyzing the Faraday rotation.

With the support of the laboratory’s intelligent computing digital reactor, the research team used the algorithm of the Zhejiang intelligent computing astronomy platform to efficiently process the data, and found through comprehensive analysis that the Faraday rotation of FRB 20190520B underwent two drastic changes in positive and negative values.

Schematic diagram of the inverting magnetic field around a fast radio burst. Image source: Science

“This shows an extreme reversal of the magnetic field around it, which means that FRB 20190520B may be in a binary system, and the companion of the binary star may be a black hole or a massive star.” Feng Yi said that this discovery will be an important step forward in the study of the origin of fast radio bursts.

“Fast radio bursts are almost always located far outside the galaxy, and exploring their origins through indirect methods such as understanding their surroundings is an important method. Therefore, it is very important to be able to determine the environmental information of the system in which the fast radio burst is located. Feng Yi told China Science News that the next step will be to determine the periodicity of changes such as Faraday’s rotation volume by continuing monitoring and computational analysis to further determine whether it is in a binary star system. (Source: China Science News Zhao Guangli)

Related paper information:https://www.science.org/doi/10.1126/science.abo6526



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