A team from the International Centre for Radio Astronomy Research (ICRAR) at Curtin University has made a groundbreaking discovery that may shed light on the enigma of long-period radio transients, a rare and extreme space phenomenon.
The research team, led by Associate Professor Natasha Hurley-Walker and including then-undergraduate student Csanád Horváth, detected an intense energy pulse emanating from deep space. The signal, found within archived data from the Murchison Widefield Array (MWA) radio telescope, recurs every three hours and lasts between 30 and 60 seconds. This makes it the longest-lasting radio transient ever recorded.
Long-period radio transients, a relatively recent addition to the scientific lexicon, produce radio waves in a way that has baffled researchers. However, this new discovery may have also pointed the way to the source of these energy bursts, potentially illuminating the nature of these elusive radio transients.
Previous transient discoveries have been located within densely star-studded regions of our galaxy, making it difficult to ascertain what specifically produces the radio waves. “To comprehend what these long-period transients are, we need a clear optical image. But when we look in their direction, there’s a star-stuffed vista that would remind one of the movie, 2001: A Space Odyssey” explained Associate Professor Hurley-Walker.
However, luck was on their side. The newly discovered transient, dubbed GLEAM-X J0704-37, was detected in a less congested area of space in the Puppis constellation, about 5000 light years away. “Since it’s far from the Galactic Plane, there are only a few stars around it. We’re confident that a particular star system is responsible for the radio waves,” said the researchers.
Using the MeerKAT telescope in South Africa, another precursor to the Square Kilometre Array Observatory (SKAO), and the SOAR observatory in Chile, the team was able to trace the radio waves to a low-mass star, an ‘M dwarf’.
This revelation sparked some intriguing questions while also providing some answers. “On its own, an M dwarf couldn’t produce the kind of energy we’re observing,” Hurley-Walker noted. “M dwarfs are low-mass stars, just a fraction of the Sun’s mass and brightness. While they make up 70 per cent of our galaxy’s stars, none are visible to the naked eye.”
“Our findings indicate that it’s part of a binary system with another object, likely a white dwarf – the remnant core of a dying star. It appears that together, they are responsible for the radio emission.”
Similar pairs have been found in the past, but this is the first time they’ve been associated with long-period radio transients.
The team is now planning further observations to definitively determine the system’s nature and explain this extraordinary space event.
A deeper dive into the MWA archives revealed that GLEAM-X J0704-37 has been active for at least a decade. However, it may have been active for much longer, suggesting that more such discoveries could be waiting in archives worldwide.
Professor Steven Tingay, MWA Director, emphasized the instrumental role of the MWA in such discoveries. “The MWA’s 55-petabyte archive, equivalent to the data storage of 55,000 high-end home computers, allows us a decade-long glimpse into our Universe. This vast collection of scientific data is a treasure trove for researchers looking to unearth more celestial phenomena,” he said.
