A gigantic Chinese telescope opens to astronomers around the world

The world's largest satellite dish radio observatory is preparing to open up to astronomers around the world, ushering in a new era of extremely delicate observations that could help in the search for gravitational and gravitational waves. to the exploration of mysterious fugitive radioactive explosions.

The five-meter spherical radio telescope (FAST) in southern China has just passed a series of technical and performance evaluations, and the Chinese government is expected to give the observatory the final green light for the start of his operations at a review meeting scheduled for next month. "We do not see any obstacles to the remaining transition," says Di Li, chief scientist at FAST. "I feel both excited and relieved."

The complex project was not without difficulties: it was designed in a radical way and initially had a hard time attracting staff, partly because of its remote location. But the profit for science will be immense. FAST will collect radio waves from an area twice as large as the single satellite dish telescope, the next largest one, the Arecibo Observatory in Puerto Rico.

The imposing size of the Chinese observatory allows it to detect extremely weak whispers from a wide range of sources throughout the universe, such as the rotating nuclei of dead stars, called pulsars, and hydrogen in galaxies distant. It will also explore a frontier of radioastronomy – using radio waves to locate exoplanets that can shelter extraterrestrial life.

Since the start of testing in 2016, only Chinese scientists have been able to conduct projects on the preliminary data of the telescope. But now, the viewing time will be accessible to researchers around the world, said Zhiqiang Shen, director of the Shanghai Astronomical Observatory and co-chair of the FAST supervision committee of the Chinese Academy of Sciences.

"I'm super excited to be able to use the telescope," says Maura McLaughlin, a radio astronomer at West Virginia University in Morgantown, who wants to use FAST to study pulsars, including hunting them in galaxies outside the Milky Way. too weak to see with today's telescopes.

During the test phase, the telescope discovered more than 100 pulsars.

Eye in the sky

It took half a decade to build a 1.2 billion yuan ($ 171 million) telescope, also called Tianyan or Eye of Paradise, in the remote Dawodang depression in Guizhou province in the south West of China. Its 500 meter wide satellite dish is made up of approximately 4,400 individual aluminum panels, on which more than 2,000 mechanical winches tilt and maneuver so as to focus on different areas of the sky. Although he sees less sky than some other state-of-the-art radio telescopes and his resolution is lower than multidish bays, the size of FAST makes him particularly sensitive, Li says.

In August and September, the instrument detected hundreds of gusts from a repeated source of rapid gusts called 121102. Many of these gusts were too weak to be perceived by other telescopes, Li added. "It's a very exciting news," said Yunfan, Gerry Zhang, who is studying BFR at the University of California at Berkeley. Nobody knows what's causing the mysterious explosions, but "the more legumes we have, the more we can learn about them," he says.

FAST examines only a tiny portion of the sky at a time, thus preventing the discovery of many new FRBs, which are ephemeral and occur in seemingly random locations. But the telescope

This "impressive sensitivity" will be useful for tracking sources in detail, says Laura Spitler, astronomer at the Max Planck Institute for Radio Astronomy in Bonn, Germany. Repeated observations may allow scientists to learn more about the environment in which a FRB has emerged and to determine if explosions vary in energy or whether they reproduce in any model.

FAST will also strengthen the efforts of an international collaboration that attempts to detect spatio-temporal ripples as they travel the galaxy, said McLaughlin. The International Pulsar Timing Array uses radio telescopes around the world to monitor regular pulsar emissions, looking for distortions that may reveal the passage of these low frequency gravitational waves. By the 2030s, FAST should have accumulated enough sensitive measurements to study individual sources of such waves, such as supermassive black hole collisions, says McLaughlin. "This is where FAST will really shine," she says.

Li is particularly excited about the study of planets outside the solar system. No exoplanet has yet been conclusively detected by his radio emissions, but FAST's ability to detect polarized and weak waves could allow him to find the first examples, explains Li. Polarized radio signals can come from planets with magnetic fields that, if similar to those of the Earth, could protect the potential sources of life against radiation and maintain the atmospheres of the planets attached.

Identifying a planet in the broad beam of FAST is a challenge because they are so small and so weak. But Li's team wants to improve the telescope's performance by adding 36 satellite dishes 5 meters wide. Although the dishes offered are relatively inexpensive and ready to use, they will improve 100 times the spatial resolution of FAST, he said.

Li hopes that FAST telescope operations will soon be transferred from the remote location to a $ 23 million data processing center currently under construction in Guiyang City. He expects moving to a big city will help attract more technical and technical staff.

The main goal of the team is now to know how to store and process the huge amount of data that the telescope will produce. The team is negotiating with the Chinese government to obtain additional funds for further data storage. "A successful exam will definitely help," he says.