An unusual radio signal has been linked to the remnant of a supernova.

Experiencing extreme cosmic events isn't always possible. As a result, astronomers "listen" to the universe using radio telescopes, capturing repetitive radio signals emitted by white dwarfs and neutron stars. However, there are exceptions. For instance, a recently discovered signal by Chinese researchers, which repeats every 44 minutes, was found to be associated with the remnant of a supernova. Scientists had never encountered anything like this before.

https://naked-science.ru/article/astronomy/neobychnyi-radiosignal-sv2024-12-05 10:00:58

A recently discovered class of radio emitters—long-period radio transients—is characterized by exceptionally long rotation periods, ranging from minutes to hours. Their nature has remained unknown for a long time. This is because such extended periods do not fit into traditional models of neutron stars or white dwarfs. Specifically, Naked Science previously reported on the binary system GLEAM-X J0704−37 (composed of a white dwarf and a red dwarf), which emitted a radio signal lasting between 30 to 60 seconds, repeating approximately every 2.9 hours.

The new signal was captured by astronomers using the Daocheng Radio Telescope (DART), repeating roughly every 44 minutes (2656.23 ± 0.15 seconds), which is slower than signals emitted by typical neutron stars.

The research findings, the text of which is available on the Cornell University preprint server (USA), indicated that the distance to the source matches that of the supernova remnant G22.7-0.2, within which lies the neutron star DART J1832-0911. However, its rotation has slowed due to an accretion disk formed by material left over from the explosion. If the astronomers' conclusions are correct, DART J1832-0911 will become the first identified long-period radio transient associated with a supernova remnant.

This is significant as it challenges existing models of neutron star evolution immediately following supernova explosions—the shedding of the outer shell and the gravitational collapse of the core at the end of the life cycle of massive stars. These objects rotate at immense speeds and emit powerful radiation from both poles. Meanwhile, the rotation axis wobbles, creating a characteristic “pulse” (which is what astronomers detect using radio telescopes).

The recorded signal, however, indicates a stable and ordered magnetic structure of the source and its slowed rotation (as a result of interaction with the accretion disk). Since optical observations using other telescopes did not reveal any visible objects in the observed region, the researchers proposed that the source is associated with the supernova remnant G22.7-0.2.

The authors of the study noted that their results will aid in understanding the evolutionary processes of neutron stars immediately after an explosion. This discovery also broadens the understanding of the nature of long-period radio transients. However, confirming or refuting the connection between the recorded signal and the supernova remnant will require further observations and studies.