Space has always been and remains a source of mysteries and surprises. Each new discovery adds to our understanding of the Universe and its mysteries. Recently, astrophysicists from Curtin University at the International Center for Radio Astronomy Research (ICRAR) in Australia made a surprising discovery that raises many questions and challenges our understanding of neutron stars and magnetars.
A strange radio signal emanating from a point 15,000 light-years away has caught the scientists’ attention. This object, called GPM J1839-10, emits radio waves every 22 minutes. And that’s incredibly slow compared to other pulsating radio waves. What’s more, archival data shows that we’ve been recording its slow pulse for more than 30 years, but so far it has managed to elude our attention.
A team of astrophysicists led by Natasha Hurley-Walker set out to solve this mystery. They concluded that the most likely explanation is that the source of the radio signal is a magnetar with a very slow rotation. Magnetars are neutron stars with extremely powerful magnetic fields, the remnants of collapsed cores of massive stars. However, GPM J1839-10 does not fit our idea of magnetars, indicating that something strange must be going on here.
Astrophysicist Natasha Hurley-Walker notes: “This remarkable object challenges our understanding of neutron stars and magnetars, which are among the most exotic and extreme objects in the Universe.”
The discovery of GPM J1839-10 is not an isolated case. Three years ago, archival data revealed a similar object in the Milky Way called GLEAM-X J162759.5-523504.3, which emitted radio waves every 18 minutes until it stopped emitting in 2018. Interestingly, the warping of the light indicated that it was traveling through a highly magnetized medium.
The researchers decided to see if there were other objects with similar behavior. They made observations of the southern sky with the Murchison Widefield Array in Australia and found an object that emits five-minute bursts of radio emission every 22 minutes. Additional observations and analysis of archival data confirmed that GPM J1839-10 has been emitting radio emissions for at least 33 years.
Natasha Hurley-Walker says: “I was five years old when our telescopes first detected pulses from this object, but nobody noticed it, and it remained hidden in the data for 33 years. They missed it because they didn’t expect to find anything like it.”
One of the key questions that arise when studying GPM J1839-10 has to do with its slow rotation. Normally, the strength of a magnetar’s magnetic field correlates with its rotation period. However, GPM J1839-10 rotates too slowly to generate powerful radio emissions. This contradicts our ideas about magnetars and raises additional questions.
Natasha Hurley-Walker explains, “Assuming it is a magnetar, this object should not emit radio waves. But we do see them. And we’re not just talking about a small burst of radio emission. This is a minute pulse of radio wave energy, and it’s been doing this for at least 33 years. Whatever the mechanism behind it, it’s extraordinary.”
This discovery challenges our ideas about neutron stars and magnetars. It shows that the Universe is always ready to surprise us and push our limits of knowledge. Further studies of GPM J1839-10 may shed light on new aspects of these exotic objects and help us better understand their mechanisms.
