Astronomers Track Down Source Of Mysterious Radio Signals From Space

Researchers from the Curtain node of the International Center for Radio Astronomy Research (ICRAR) have tracked down a possible explanation for the rare astrophysical event known as long-period radio transients. Associate Professor Natasha Hurley-Walker, and Csanad Horvath, an undergraduate student at the time, discovered the pulse of bright energy among archival low-frequency data from the MWA (Murchison Widefield Array).

The energy pulse, which occurs every three hours and lasts only 30-60 seconds, is the longest-period radio transient ever detected, according to the new research. Long-period transients are fairly new, and have been an ongoing mystery as to how they generate radio waves. However, with the new discovery, researchers are hopeful they have identified the source of the energy burst, and possibly gained new insight into long-radio transients.


“The long-period transients are very exciting, and for astronomers to understand what they are, we need an optical image. However, when you look toward them, there are so many stars lying in the way that it’s like 2001: A Space Odyssey. ‘My god, it’s full of stars!’,” explained Hurley-Walker.

One thing that made the discovery a bit easier is the fact that the transient, named GLEAM-X J0704-37, is located on the outskirts of the Milky Way. It is “in a much emptier region of space in the Puppis constellation, around 5,000 light years away,” according to the researchers.

The fact that there are only a handful of stars nearby gives the team more confidence in being able to say that one star system, in particular, is generating the radio waves. The one specific star responsible for the radio waves was pinpointed using the MeerKAT telescope in South Africa. In a follow-up observation using the SOAR observatory in Chile, the team was able to determine the star’s spectrum, finding it was a low-mass star, known as an ‘M dwarf.’


Professor Hurley-Walker remarked the finding both answered and raised new questions, saying “An M dwarf alone couldn’t generate the amount of energy we’re seeing.”

The professor continued, “The M dwarfs are low-mass stars that have a mere fraction of the Sun’s mass and luminosity. They constitute 70 per cent of the stars in the Milky Way, but not one of them is visible to the naked eye.” She added that their data suggested that it is in a binary orbit with another object, which is likely a white dwarf. “Together, they power radio emission.”

The team is currently working on follow-up observations that will hopefully give them conclusive evidence supporting their new findings, and the explanation of this astrophysical event of long-period radio transients.