Beijing, January 6 (Xinhuanet) -- The reporter learned from the National Astronomical Observatory of the Chinese Academy of Sciences that China's Tianyan FAST has been running with high quality since January 11, 2020 through the national acceptance, and in 2021, relying on the FAST National Astronomical Observatory to achieve new important scientific achievements in the field of international astronomical frontiers such as neutral hydrogen spectral line measurement of interstellar magnetic field, fast radio bursts, and pulsar search.
Panorama of the "China Sky Eye" taken on December 19, 2021 (taken during maintenance, drone photo). Photo by Xinhua News Agency reporter Ou Dongqu
Jiang Peng, executive deputy director and chief engineer of FAST Operation and Development Center, introduced that on March 31, 2021, FAST officially opened to the world for sharing and solicited observation applications from astronomers around the world. A total of 7216 hours of observation applications were received from different countries, and 27 international projects from 14 countries (excluding China) were finally approved, and scientific observations were launched in August 2021.
"The efficiency and quality of FAST operation have been continuously improved, and the annual observation time has exceeded 5300 hours, which has far exceeded the work efficiency expected by international peers, and has played an important supporting role for fast scientific output." According to Jiang Peng, FAST has become the most efficient device in the world since its operation. In 2021, a number of important scientific research achievements have been made based on FAST, including significant progress in measuring interstellar magnetic fields by FAST neutral hydrogen lines that challenge the classical star formation picture.
On January 5, at a press conference held by the National Astronomical Observatory of the Chinese Academy of Sciences, Li Jing, chief scientist of FAST's Operation and Development Center, introduced fast's latest major achievements in the field of neutral hydrogen. Photo by Xinhua News Agency reporter Jin Liwang
At the press conference, Li Jing, chief scientist of FAST Operation and Development Center, introduced that magnetic fields play an important role in the production of stars, planets and life, and the process is complex, so the "magnetic flux problem" is one of the three classic problems in star formation, and the measurement of interstellar magnetic field strength of molecular clouds is a common challenge in the global astronomical community.
According to reports, neutral hydrogen is the most abundant element in the universe, widely exists in different periods of the universe, and is one of the best tracers for the distribution of matter at different scales. The FAST telescope is a powerful tool for detecting dark and neutral hydrogen sources. Li's team developed and named the original neutral hydrogen narrow line self-absorption (HINSA) method. Relying on the unparalleled sensitivity of the FAST telescope and the excellent optical path design, the detection of the HINSA Zeman effect was realized for the first time, and a high-confidence interstellar magnetic field measurement with a strength of 3.8±0.3 micro gauss was obtained, which was a breakthrough from 0 to 1 in detecting the magnetic field of molecular clouds by means of atomic radiation.
FAST detected a magnetic field that was only one hundred thousandth of Earth's, at least 3 to 4 times weaker than the magnetic field predicted by the Standard Model of Star Formation. THE FAST results reveal that molecular clouds can reach a magnetic supercritical state ahead of time at the dense cloud nucleus stage, and there may be a more efficient magnetic field dissipation mechanism than the Standard Model to cause star formation to occur ahead of schedule. This achievement is expected to expand the neutral hydrogen narrow line self-absorption method into an important systematic probe for interstellar magnetic field measurement. Li Told reporters.
The research team used the original neutral hydrogen narrow line self-absorption method to use FAST to obtain the first high-confidence Zehmann effect measurements in the protostar nuclear envelope. The discovery of a coherent magnetic field structure in the interstellar medium from cold neutral gas to protostar nuclei is different from the prediction of the Standard Model, providing important observational evidence for solving the "magnetic flux problem", one of the three classical problems of star formation. The result paper was officially published in the form of a cover article in the international academic journal Nature on January 6, 2022, Beijing time.
Panorama of the "Chinese Sky Eye" in the sunset taken on December 19, 2021 (taken during maintenance, drone photo). Photo by Xinhua News Agency reporter Ou Dongqu
Fast radio bursts (FRBs) are the brightest radio bursts in the universe, with unknown origins, and are the latest hotspots in astronomy. At the press conference, Wang Pei, an associate researcher at the National Astronomical Observatory, introduced that hundreds of cases of FRB have been detected, and only a few of them have shown repeated outbreaks. FRB121102 is the first repeat burst known to humans, becoming the first FRB to be precisely located in 2017 to confirm its host galaxy.
The research team used FAST to observe fast radio burst FRB121102, detected 1652 burst events in about 50 days, obtained the largest sample of fast radio burst event to date, exceeded the total number of burst events published in all previous articles in the field, and revealed for the first time the complete energy spectrum of the rapid radio burst burst rate and its bimodal structure, and the result paper was published in the international academic journal Nature on October 14, 2021.
According to Wang Pei, the FAST Multiscience Goal Survey has discovered at least 6 new FRBs, which is making a unique contribution to revealing the mechanism of mysterious phenomena in this universe and advancing this new field of astronomy.
On January 5, at a press conference held by the National Astronomical Observatory of the Chinese Academy of Sciences, Han Jinlin of the National Astronomical Observatory introduced the important progress of FAST in the search for pulsars. Photo by Xinhua News Agency reporter Jin Liwang
Pulsars are the "remains" of massive stars after their death, with a sugar cube-sized volume of hundreds of millions of tons of mass, and pulsars can emit highly periodic pulses with periods ranging from 1.4 milliseconds to 23 seconds. Known as the "millisecond pulsar," the short-period pulsar rivals the best atomic clocks on Earth. The discovery of pulsars is one of the main scientific targets of observations by large international radio telescopes.
At the press conference, Han Jinlin, a researcher at the National Astronomical Observatory, introduced that FAST is equipped with a 19-beam L-band receiver, which is the world's most powerful pulsar search weapon. The research team not only detected 550 previously known pulsars from the milky sea of stars, but also discovered 279 new pulsars, of which 65 were millisecond pulsars and 22 in binary systems. The relevant paper was published in the domestic academic journal "Astronomy and Astrophysics Research" in May 2021.
On December 17, 2021, the staff carried out maintenance of the feeder cabin of "China Sky Eye". Photo by Xinhua News Agency reporter Ou Dongqu
The reporter learned that based on the international leading advantage of FAST sensitivity, the combination of FAST and the Fermi Gamma-ray Observatory's Large Field telescope (Fermi-LAT), an important space astronomical facility in the high-energy band, to carry out space-space integration coordination and follow-up observations has the potential to produce major scientific breakthroughs.
The international cooperation team led by Li Jing and Wang Pei of the National Astronomical Observatory discovered a number of pulsars and carried out multi-band observation and analysis. The relevant results were published in the domestic academic journal Science in China in December 2021. "Multi-band cooperative observation not only opens up a new direction for FAST pulsar search, but also opens up a new way to study the electromagnetic radiation mechanism of pulsars, providing more samples for the evolution of sub-star families and the detection of gravitational waves." Li Said.
On January 5, at a press conference held by the National Astronomical Observatory of the Chinese Academy of Sciences, Academician Wu Xiangping introduced the FAST follow-up scientific research program. Photo by Xinhua News Agency reporter Jin Liwang
For fast follow-up research plan, Wu Xiangping, academician of the Chinese Academy of Sciences and researcher of the National Astronomical Observatory, said that based on the obvious advantages of ultra-high sensitivity, FAST has become a celestial weapon in the field of medium and low frequency radio astronomy, and will produce scientific achievements to deepen human understanding of the universe in the future in the direction of the origin and physical mechanism of fast radio bursts, neutral hydrogen universe research, pulsar search and physical research, pulsar timing and low-frequency gravitational wave detection.