Astronomers have discovered a strange radio signal coming from deep space that defies current scientific understanding. The signal labeled ASKAP J1935+2148 repeats every 53.8 minutes, the longest recorded period for such a phenomenon.
Published in the journal Astronomy of naturethe discovery, made with Australia’s Square Kilometer Array Pathfinder (ASKAP) radio telescope, has astronomers both baffled and excited about the potential implications for our understanding of the universe.
In recent years, astronomers have identified several mysterious objects that emit repetitive radio signals. in 2020 GLEAM-X J162759.5-523504.3which is located near the galactic center, was observed emitting unusually bright flashes for just three months before dying out.
Another object, discovered last year, GPM J1839-10behaves like a slow pulsar, emitting five-minute radio bursts every 22 minutes.
However, the newly discovered radio signal works a little differently.
The signal was first detected during routine observations by the ASKAP radio telescope located in Australia’s Wajarri Yamaji country. The telescope, known for its wide field of view, was tracking the gamma-ray burst when it encountered ASKAP J1935+2148. The signal stood out due to its unique characteristics, including a long period and distinct emission states.
Dr. Manisha Caleb, an astrophysicist at the University of Sydney and lead author of the study, said in a press release that she thinks it could be a new type of neutron star.
“It is very unusual to discover a neutron star candidate emitting radio pulsations in this way,” she said Press Release. “The fact that the signal repeats at such a slow rate is extraordinary.”
After the initial detection, the team conducted additional observations for several months using ASKAP and the more sensitive MeerKAT radio telescope in South Africa.
The ASKAP telescope, equipped with a special type of radio receiver, was assembled in a grid pattern to scan the sky at a frequency of 887.5 MHz. The signals it captured were split into smaller parts to make the image clearer, and the data was processed every 10 seconds to pick up the bright pulses from ASKAP J1935+2148. Meanwhile, the MeerKAT telescope, operating in a higher frequency range (0.86-1.71 GHz), provided more detailed and sensitive observations.
“What’s interesting is how this object exhibits three distinct emission states, each with completely different properties,” Caleb explained. “The MeerKAT radio telescope in South Africa played a key role in distinguishing between these states. If the signals weren’t coming from the same point in the sky, we wouldn’t believe it was the same object producing these different signals.”
According to the study, astronomers observed bright linear pulses that lasted anywhere between 10 and 50 seconds, followed by fainter pulses that followed a circular pattern that lasted only 370 milliseconds, followed by a lull when no pulses were detectable. Then everything would repeat itself.
This new mysterious radio signal challenges current astrophysical models of neutron stars and white dwarfs. Known for their rapid rotation, neutron stars typically complete a rotation in seconds or fractions of a second. ASKAP J1935+2148’s duration of 53.8 minutes places it in the “pulsar valley of death”, where no detectable radio signals are expected. In other words, if it’s a neutron star, it shouldn’t emit anything.
One hypothesis is that ASKAP J1935+2148 could be an ultra-long-period magnetar, a type of highly magnetized neutron star. However, slow rotation and continued radio emission are unusual for such objects. Another possibility is a highly magnetized white dwarf, but no known white dwarfs have been observed to emit radio waves in this way, making this explanation less likely.
Caleb and her team currently believe that this radio signal likely came from a slowly rotating neutron star or from a binary system with a neutron star or another white dwarf. They admit that this is only a hypothesis because something like this has never been observed before and more research needs to be done.
“It might even make us rethink our decades-old understanding of neutron stars or white dwarfs,” Caleb concluded. “How they emit radio waves and what is their population in our Milky Way Galaxy.”
MJ Banias covers space, security and technology with The Debrief. You can email him at mj@thedebrief.org or follow him on Twitter @mjbanias.