China News Service, Beijing, June 9 (Reporter Sun Zifa) One is the most mysterious and brightest radio burst phenomenon in the universe-Fast Radio Burst (FRB), the other is the world's largest single-aperture telescope, known as "China's Sky Eye" The 500-meter Aperture Spherical Radio Telescope (FAST), the two have a strong interaction and scientific "collision", what kind of astronomical "spark" will be produced has been attracting attention.
According to the latest news from the National Astronomical Observatory of the Chinese Academy of Sciences, an international team led by researcher Li Di, the chief scientist of "China Sky Eye", has discovered the first case, It is also the only case of persistently active repeating fast radio bursts so far, named "FRB 20190520B".
Four bursts of FRB 20190520B detected by FAST and FAST for the first time.
Photo courtesy of the National Astronomical Observatory
The research team then organized a number of international equipment to observe the sky and the earth, and integrated data from radio interference arrays, optical, infrared telescopes, and space high-energy observatories to locate FRB 20190520B in a metal-poor dwarf galaxy 3 billion light-years away from the earth, confirming its The near-source region has the largest electron density known to date, and the second persistent radio source counterpart (PRS) of a fast radio burst to date has been discovered.
This important discovery of the splendid astronomical "spark" reveals that the complex environment around active repeating bursts has characteristics similar to super-bright supernova explosions, which challenges the traditional view of FRB dispersion analysis, and provides a foundation for the construction of FRB evolution models, Lay a solid foundation for understanding this dramatic cosmic mystery.
The research paper was published online in the internationally renowned academic journal "Nature" on the night of June 8, Beijing time.
Composite image of the Chinese Sky Eye (FAST) (bottom) and the Very Large Astronomical Array Telescope (VLA) (top).
Photo courtesy of the National Astronomical Observatory
How the First Persistently Active Fast Radio Burst Was Detected
Dr. Niu Chenhui, the first author of the paper and a young scholar at the National Astronomical Observatory of the Chinese Academy of Sciences, said that fast radio bursts can release the energy that the sun can radiate in about a whole year in 1 millisecond. The first case of repeated bursts of fast radio bursts broke people's traditional understanding of it.
At present, this field has become one of the latest research hotspots in astronomy. Nearly 500 FRBs have been announced around the world, and less than 10 of them have active outbreaks (that is, frequent outbreaks within their window period), but no sustained activity has been found before. of repeating fast radio bursts.
In the process of systematically processing the detection data of "China Sky Eye", he found that the data on May 20, 2019 had repeated high dispersion pulses, and named it FRB 20190520B by convention. When this fast radio burst was first detected, showing signs of activity.
Based on this discovery, the research team, in cooperation with the Very Large Array Telescope in the United States, completed precise positioning on the sub-arcsecond level in July 2020, and detected a corresponding dense continuous radio source.
Group photo of the author representatives of the paper, Researcher Zhu Weiwei, Researcher Li Di, Dr. Niu Chenhui, and Researcher Cai Zhaowei (from left to right) of the National Astronomical Observatory of the Chinese Academy of Sciences.
Photo by China News Agency reporter Sun Zifa
Subsequently, the research team determined the host galaxy and redshift of FRB 20190520B through the Palomar 200-inch telescope and the Keck telescope in the United States, the Canada-France-Hawaii telescope and the Subaru near-infrared optical telescope in Japan, and deduced that its host galaxy contributed to the total 80% of the dispersion value is the highest among all FRB sources known so far.
Further combining the scattering characteristics, the research team proposes that the dispersion of the host galaxy mainly comes from the region adjacent to the source of the fast radio burst, and the high dispersion value caused by the high electron density in this region also makes FRB 20190520B far away from the classical dispersion-redshift relationship.
A group photo of the corresponding author of the paper, Researcher Li Di of the National Astronomical Observatory of the Chinese Academy of Sciences (left), and the first author of the paper, Dr. Chenhui Niu of the National Astronomical Observatory of the Chinese Academy of Sciences.
Photo by China News Agency reporter Sun Zifa
What are the similarities and differences with the previous discovery of similar fast radio storms in the United States
Niu Chenhui pointed out that the FRB 20190520B discovered by the "China Sky Eye" is very similar to the FRB 20121102A previously discovered by the Arecibo telescope in the United States.
FRB 20121102A is the first FRB repeating FRB discovered by humans and the first FRB that has been located. It is also the only FRB previously confirmed to have a dense radio source counterpart.
Both are extremely active and have complex electromagnetic environments, while FRB 20190520B has more extreme characteristics in all aspects: for example, FRB 20121102A has an active eruption period, but FRB 20190520B has never stopped erupting. So far, "China Sky Eye" has detected Hundreds of bursts to the latter.
Niu Chenhui concluded that, as the first continuous active and repeated FRB, FRB 20190520B is the only FRB that has not been observed to stop erupting.
The electron density near the source of FRB 20190520B is the highest so far, with a very complex electromagnetic environment, and it is the second case so far to discover a fast radio burst accompanied by a persistent radio source.
He believes that FRB 20190520B is very similar to FRB 20121102A, which may represent the early stage of the evolution of FRBs, which is expected to help uncover the mystery of the origin of FRBs.
Dr. Chenhui Niu, the first author of the paper and the National Astronomical Observatory of the Chinese Academy of Sciences, introduced the results of the first continuous active and repeated FRBs discovered by "China Sky Eye".
Photo by China News Agency reporter Sun Zifa
What is the significance of the important discovery of "China's Sky Eye"?
After the publication of the preliminary results of this important discovery study based on the detection data of the "China Sky Eye", it has attracted widespread attention from the international astronomical community, and based on it, several innovative model articles have been published, including the scattering time scale model and the interpretation of supernova explosions.
Researcher Li Di said that based on the recent observation data of "China Sky Eye", FRB 20121102A and FRB 20190520B are likely to be in the initial stage of fast radio bursts.
The continuous observation of the "China Sky Eye", especially the implementation of the "Fast Radio Storm Sky Survey" priority major project, is expected to establish a new picture of the evolution of fast radio storms.
He revealed that at least 6 new fast radio bursts have been discovered so far in the "Multi-Scientific Target Simultaneous Sky Survey" priority major project of "China Sky Eye", which is working to reveal the mechanism of this mysterious phenomenon in the universe and promote research in this new field of astronomy. make a unique contribution.
The corresponding author of the paper and researcher Li Di of the National Astronomical Observatory of the Chinese Academy of Sciences introduced the results of the "China Sky Eye" discovery of the first continuous active and repeated fast radio burst.
Photo by China News Agency reporter Sun Zifa
In response to the widespread speculation about whether FRBs are signals for aliens to contact the earth, and the related issues that "China Sky Eye" is clearly included in the scientific goal of "participating in the search for extraterrestrial civilizations", Li Di believes that although various Paranormal phenomena have not been incorporated into the mainstream framework of the academic world, but they have provided enough space for people to imagine.
Duncan Lorimer, the discoverer of fast radio bursts and a professor at West Virginia University, commented that based on the characteristics of the new fast radio burst FRB 20190520B and the existence of its continuous radio source, he believes that fast radio bursts may come from a variety of celestial bodies, and there may be different classifications.
As the sample of FRBs continues to grow, it is expected that in the next few years, intriguing classes of objects in FRBs will be explained in detail.
Jonathan Katz, an expert on fast radio storm theory and a professor at Washington University in St. Louis, said that the discovery of FRB 20190520B helps to understand the surrounding environment of fast radio storms, and then reveal its radiation mechanism.
Dai Zigao, a professor at the Department of Astronomy at the University of Science and Technology of China, pointed out that the study of FRB 20190520B shows that its surrounding environment appears to be particularly dense and highly magnetized, which in turn means that the origin of the burst (now widely considered to be a neutron star) is relatively young and may be in a binary star system Or supernova remnants, which have important scientific implications for understanding the surrounding environment and physical origin of FRBs.
Academician Chang Jin, director of the National Astronomical Observatory of the Chinese Academy of Sciences, said that although the discovery of FRB 20190520B is somewhat accidental, it is inevitable that China will continue to increase investment in large scientific installations to achieve breakthroughs, thanks to the contributions of generations of astronomers.
He hoped that in the near future, in the frontier fields of world science and technology such as dark matter, neutral hydrogen, and gravitational wave detection, Chinese scientists can make more original and major discoveries and achieve greater scientific breakthroughs.
(Finish)