Record-Breaking Astrophysical Discovery Unveils Mystery of Long-Period Radio Transients
Researchers from the Curtin node of the International Centre for Radio Astronomy Research (ICRAR) have made a groundbreaking discovery that could reshape our understanding of rare and extreme astrophysical phenomena known as long-period radio transients.
Leading the research, Associate Professor Natasha Hurley-Walker, alongside then-undergraduate student Csanád Horváth, uncovered a powerful pulse of bright energy from deep space within archival low-frequency data from the Murchison Widefield Array (MWA)—a precursor to the Square Kilometre Array Observatory (SKAO). This pulse, occurring every three hours and lasting 30-60 seconds, is now the longest-period radio transient ever recorded.
Cracking the Mystery of Long-Period Radio Transients
Long-period radio transients are relatively new to science, with their mechanisms largely unknown. This discovery offers a potential breakthrough in identifying their sources. Unlike previously discovered transients, which were buried deep within the bustling Milky Way, this new transient was found in a less crowded region of space, providing clarity previously unattainable.
Associate Professor Hurley-Walker expressed her excitement, saying, “The long-period transients are very exciting, and for astronomers to understand what they are, we need an optical image. But 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!’”
The newly discovered transient, GLEAM-X J0704-37, lies on the outskirts of the Milky Way in the Puppis constellation, approximately 5,000 light-years away. Its isolated position allowed researchers to precisely identify the source of its radio waves.
A Unique Binary Star System
Using the MeerKAT telescope in South Africa, the team pinpointed the radio waves to a specific star system. Further analysis at the SOAR observatory in Chile revealed that the source is an M dwarf—a low-mass star with a fraction of the Sun’s mass and luminosity, common in the Milky Way but invisible to the naked eye.
However, the energy output of GLEAM-X J0704-37 is too substantial for an M dwarf alone, leading researchers to conclude it is part of a binary system with a white dwarf—the remnant core of a dying star. This pairing is believed to power the intense radio emissions.
“An M dwarf alone couldn’t generate the amount of energy we’re seeing,” Hurley-Walker explained. “Our data suggests it is in a binary system with a white dwarf, which together produce the radio emission.”
A Decade of Hidden Activity
The MWA archives revealed that GLEAM-X J0704-37 has been active for at least ten years, since the MWA began its observations. This suggests that many more such transients could be lurking within global astronomical archives, waiting to be discovered.
Professor Steven Tingay, Director of MWA, highlighted the significance of the archive, stating, “The MWA has fundamentally enabled these discoveries. With a 55-petabyte archive of observations, it’s like having the data storage of 55,000 high-end home computers—a gold mine for discovering more phenomena in our Universe.”
Future Research Directions
The team is conducting follow-up observations to confirm the nature of this binary system and further unravel the mystery of long-period radio transients. This discovery not only deepens our understanding of these enigmatic phenomena but also opens new pathways for exploring the Universe’s hidden marvels.
