BEIJING: Chinese astronomers and their international peers have refreshed the limits for Galactic observation using China’s Five-hundred-meter Aperture Spherical Radio Telescope (FAST) and South Africa’s MeerKAT array radio telescope as they completed high-precision observations of the Milky Way’s globular clusters.
Globular clusters, some of the oldest celestial bodies in the Milky Way, typically consist of millions of stars, including pulsar neutron stars. These highly magnetized pulsars emit regular electromagnetic pulses with exceptional precision, which carry valuable information about the interstellar matter and magnetic fields, traveling across vast space to reach Earth.
FAST is adept at capturing the faintest cosmic ripples, the signals from pulsars located millions of light years away, while MeerKAT’s 64-antenna array focuses on tracking signals across a broader sky area.
The project led by Tsinghua University marks the first deep collaboration between these two world-leading radio telescopes in the study of globular clusters.
Participating astronomers attributed the accomplishment to the synchronization between the two nations’ telescopes.
“By combining equipment from the Southern and Northern Hemispheres, which are of different capabilities, we have more than doubled our observational sample,” said professor Li Di from Tsinghua University.
This collaboration successfully obtained polarization rotation measurements of 43 pulsars from eight globular clusters. Such measured results are a key indicator of the strength of the cosmic magnetic field. Notably, the research found that seven of these globular clusters showed no detectable ionized gas, indicating an exceptionally “clean” environment, according to astronomers.
“We call it the ‘dust-free realm’ among the Milky Way’s ancient celestial bodies. Why have these globular clusters remained so clean after such a long process of evolution? This is a new question for us. Scientists now speculate that many smaller but highly active members of the globular cluster ‘family,’ such as white dwarfs and neutron stars, are constantly radiating energy, ‘blowing away’ the electron ‘dust’ created by other stars,” said Li.
Both sides expect further collaborations on pulsar mutations and interstellar turbulence, and even exploration of possible signals from extraterrestrial civilizations.
