Cosmic radio signal: astronomers detect a pulsar where none was expected for the first time in decades
A team of scientists from the National Astronomical Observatories of the Chinese Academy of Sciences and Tsinghua University has recently detected pulsed radio emission from a central compact object, marking the first such discovery in decades and providing crucial evidence for understanding the formation and evolution of young neutron stars. The universe is full of silent stars, but silence can be deceptive. Central compact objects — neutron stars at the centres of supernova remnants — were long considered "radio‑quiet." They could not be heard, and scientists assumed they simply did not emit radio waves. But Chinese astrophysicists have proven they are not silent. Their voice is simply too faint to be picked up through the noise of space. This discovery, made in China's observatories, overturns decades of established understanding.
Located in the centres of supernova remnants, central compact objects (CCOs) are among the most enigmatic neutron stars. CCOs shine brightly in the thermal X‑ray band, but for decades they evaded detection by large radio telescopes, leading to the belief that they are intrinsically radio‑quiet and possess exceptionally weak magnetic fields. In a recent research paper published in Nature Astronomy, the team showed that the prototypical young CCO 1E 1207.4–5209 is actually a weak radio pulsar rotating with a period of 0.4 seconds in the X‑ray range. Analysis of its polarisation shows that the radio beam crosses the line of sight near the magnetic pole, confirming that its radio faintness is intrinsic. After the supernova remnant dissipates, this source would be misidentified as a pulsar that appears to be 40 years old. The low radio flux density of CCOs may explain why many supernova remnants lack detectable radio pulsars, and suggests the existence of a hidden population of young, slowly rotating neutron stars.
Central compact objects are neutron stars left behind after supernova explosions. They emit in the X‑ray range, but until now were considered radio‑quiet. The discovery shows that the source 1E 1207.4–5209 is actually a weak radio pulsar with a rotation period of 0.4 seconds. This means that many other CCOs may be similarly "hidden" pulsars, simply with emissions too faint to be detected from Earth. The work was published in Nature Astronomy. The discovery reshapes our understanding of neutron star populations and how they evolve after a supernova explosion.
When we look at the night sky, we see only a fraction of what is out there. Behind the bright flashes of supernovae lie objects that have eluded detection for decades. Chinese astrophysicists have proven that the universe does not stay silent — it simply speaks on frequencies we cannot always hear. And this radio signal, captured by powerful telescopes, is not just a scientific sensation. It is a reminder that space holds secrets waiting to be uncovered. Sometimes, to hear them, we just need to tune in to the right wavelength.
As reported by CCTV+, the discovery by Chinese scientists opens new avenues for studying neutron stars and could lead to a revision of models of compact object evolution in the universe.
