The 500-meter aperture spherical radio telescope (FAST) located in Dawotai, Pingtang County, Guizhou Province, is known as the "China Sky Eye", and since passing the national acceptance in January 2020, FAST has been operating efficiently for 2 years, and has made a number of important scientific achievements in the fields of pulsar discovery and neutral hydrogen line measurement of interstellar magnetic field. At the same time, FAST officially opened up to the world in 2021, and 27 international projects in 14 countries began to launch scientific observations. Li Jing, a researcher at the National Astronomical Observatories of the Chinese Academy of Sciences and chief scientist of FAST, said in an interview with the Global Times reporter recently that FAST's current achievements have exceeded previous expectations, and in the future it will gradually assume the role of the world's largest single-aperture telescope - Arecibo Telescope, providing more observation opportunities for global scientists.
"China's Sky Eye" infographic
A number of important scientific research results showed greater than expected efficiency
Earlier this month, the National Astronomical Observatory announced a number of important scientific research achievements made by scientists relying on FAST, including the major progress made in the measurement of interstellar magnetic fields by FAST neutral hydrogen spectral lines; obtaining the largest rapid radio burst event sample to date, revealing for the first time the complete energy spectrum of fast radio bursts and their bimodal structure; the "Silver Road Surface Pulsar Snapshot Survey" project continued to discover millisecond pulsars; multi-band cooperative observations opened up pulsar searches for new directions, and opened up new ways to study the electromagnetic radiation mechanism of pulsars.
FAST chief scientist Li Jing told the Global Times reporter that from the completion of FAST to the acceptance, after 3 years of arduous debugging, the engineering team has been adjusted and improved as much as possible for the problems in the first-line observation practice, so that there is currently such an unintended efficiency, and the future can be further improved.
Among the above scientific research results, FAST's exploration of pulsars has achieved the most intuitive results, with a total of 509 pulsars discovered, and it has become the single telescope with the most pulsars discovered in the past two years. A pulsar is a fast-spinning neutron star that constantly emits electromagnetic pulse signals.
Li Jing told the Global Times reporter that due to the above characteristics, the accurate clock signal provided by the pulsar can become a tool for basic physical measurements on the cosmic scale, or even the only available accurate clock at the Galactic scale. The study of pulsars is of great significance for both astronomy and fundamental physics.
Li Said that after another 5-10 years, Chinese scientists are expected to make revolutionary breakthroughs in the field of pulsar research relying on FAST. FAST is already planning a pulsar search for the Andromeda galaxy, the Milky Way's "sister galaxy." Scientists have never previously found a radio pulsar in a spiral galaxy outside the Milky Way.
Fast radio bursts (FRBs) are one of the hottest and fastest-growing fields of astronomy today than pulsars. Li said that fast radio bursts are the brightest radio bursts in the universe, releasing the sun's energy for an entire year in 1/1000 of a second.
In 2019, an international collaboration team led by Li Jing and scientists such as Wang Pei and Zhu Weiwei of the National Astronomical Observatory obtained the largest sample of rapid radio burst events to date, and observed 1652 outbreaks of fast radio burst FRB121102 in a month and a half. The discovery exceeds the total number of outbreak events previously published in all previous articles in the field and reveals for the first time the complete energy spectrum of fast radio bursts and their bimodal structure. Li Told the Global Times that this achievement has pushed the field to a new stage of high-statistical research.
Relying on FAST, the international cooperation team led by Li Andong and the National Astronomical Observatory KyoDo-chong also used the original neutral hydrogen narrow line self-absorption method (HINSA) to obtain the high-confidence Zeman effect measurements in the protostar nuclear envelope for the first time, providing important observational evidence for solving the "magnetic flux problem", one of the three classical problems of star formation. The paper was officially published earlier this month in the form of a cover article (small picture) in the international academic journal Nature. Li said that in the future, scientists can use HINSA to make more systematic measurements, which is expected to fundamentally change the current understanding of the interstellar magnetic field.
Nature magazine
More and more time will be opened to the world for sharing
FAST is the world's largest radio telescope that inherits and surpasses the Arecibo Telescope in the United States. At the end of 2020, the Arecibo telescope collapsed, and FAST took on a more important role and responsibility. The Global Times reporter noted that many of the scientific research results released by the above-mentioned national astronomical observatories were completed by international cooperation teams.
On March 31, 2021, FAST officially opened its shares to the world, soliciting observation applications from astronomers around the world. The call for a total of 7216 hours of observation applications was received from different countries, and 27 international projects from 14 countries (excluding China) were approved, and scientific observations were launched in August 2021. "The field of astronomy itself focuses on open cooperation, as Nan Rendong, the father of the 'Eye of Heaven', often mentioned, human beings have the same sky." Li Said.
Currently, FAST has 10% of its observation time available for international projects. Li said that once foreign scientists are allocated time, they can arrange their own time and observation plans, which are implemented by FAST, and these projects also need to be reviewed by international peers.
According to Li, the scientists applying for the FAST program are mainly from the United States, Europe and Australia, and he is most impressed by the cooperation with Australian scientists. Li Told the Global Times that the cooperation between Chinese and Australian scientists in the field of radio astronomy was carried out very early, as early as the establishment of diplomatic relations between the two countries, Australian radio astronomer Christensen came to China in 1963 to assist China in establishing radio astronomy equipment, "which is even earlier than 'ping-pong diplomacy'." "In 2017, FAST, which is still in the debugging period, released the first results and found that 6 new pulsars are the result of collaboration with Australian scientists. Li said that at that time, FAST searched for very good signals, and then used Australia's mature telescope to verify, this cooperation improved fast efficiency. Li Said: China and Australia have a good tradition in the field of radio astronomy, and the current exchanges and cooperation between scientists of the two countries are also very smooth.
Li Said said that previously scientists around the world would use the American Arecibo Telescope for observation and research, and in the future FAST will gradually assume such a role, and more and more time will be opened to the world.
Chris Kruchel, a professor at the University of Illinois and a well-known scientist in the field of international interstellar magnetic field measurement, visited FAST a few years ago. He said he was very impressed with FAST's engineering and staff because it is by far the world's largest and strongest single-antenna radio telescope, giving FAST the potential to produce breakthrough scientific research. "I look forward to further work on FAST, which will expand our understanding of the principles of star formation and will advance other areas of astrophysics."
The search for extraterrestrial civilizations is not science fiction
As the chief scientist of FAST, Li Wei expects that FAST will produce new results in three directions in the future: first, there will be more important progress in depicting the gas environment of the Milky Way; second, in the field of fast radio storms, Chinese scientists are currently writing or have submitted papers to put forward original ideas and achieve cutting-edge results on the unified nature of the fast radio storm environment and the physical mechanism of its origin; third, some new progress has been made in exploratory fields such as suspected extraterrestrial civilization signals and exoplanets.
Li Told the Global Times that the FAST proposal written by Mr. Nan Rendong and submitted to the state has put forward five major scientific goals, including the search for extraterrestrial civilization. "From the perspective of our front-line experimenters, searching for extraterrestrial civilization is not a science fiction thing at all, it is part of our daily work." Li Said that the search for extraterrestrial civilization is mainly to search for communication signals, that is, narrowband pulses.
In 1936, the Berlin Olympics became the first Olympic Games in human history to be televised. Li said that at that time, large-scale wireless television signals had been emitted into space, even flying out of the solar system, and could be received by extraterrestrial civilizations (if they existed). "The classic 'don't answer' in 'The Three-Body Problem' actually has no meaning, the reality is that humans can no longer recover the wireless signals emitted over the past few decades." Li Said.
FAST will soon also usher in a new partner in space - the sky survey space telescope planned for the Chinese Tiangong space station, also known as the "Chinese Hubble Telescope". Talking about the "heaven-earth cooperation" of FAST and sky survey telescopes in the future, Li Jing said that optical telescopes such as sky survey telescopes are still the mainstream of astronomy, which can be seen from the input. In the future, FAST will try to cooperate with the work of the sky survey telescope. Taking transient phenomena such as fast radio bursts as an example, FAST can discover some new sources and then conduct more in-depth research by the Sky Survey Telescope.
According to the development status of the international radio astronomy field, FAST is currently 10 years ahead of the world, and the giant radio telescope array "square kilometer array", which is participated by many countries including China and is expected to be put into use in 2030, is expected to become the largest and most advanced equipment in the field. "Front-line astronomers are happy to see these developments, and if there is no greater investment than FAST in the field of radio astronomy in 10 years, it proves that this is not a booming industry." But even after the "Square Kilometer Array" was put into use, FAST still had its unique features, Li said.
Global Times-Global Network/Zhao Jueheng Deng Xiaoci
Source: World Wide Web