July 19 () –
An international team led by astronomers from the Curtin University node of the International Center for Radio Astronomy Research (ICRAR) in Australia has discovered a new type of stellar object that challenges the understanding of the physics of neutron stars. The object could be an ultralong-period magnetar, a rare type of star with extremely strong magnetic fields that can produce powerful bursts of energy.
Until recently, all known magnetars emitted energy at intervals ranging from a few seconds to a few minutes. The newly discovered object emits radio waves every 22 minutes, making it the longest-period magnetar ever detected.
Astronomers discovered the object using the Murchison Widefield Array (MWA), a radio telescope located in Wajarri Yamaji Country, in the Western Australian outback. Lead author Dr. Natasha Hurley-Walker explains that the magnetar, named GPM J1839-10, is located 15,000 light-years from Earth, in the constellation of Scutum. “This extraordinary object challenges our understanding of neutron stars and magnetars, which are some of the most exotic and extreme objects in the Universe.” recognize.
The stellar object is only the second of its kind detected so far, after the first was discovered by research student Tyrone O’Doherty of Curtin University. At first, the scientists could not explain what they had found.
In January 2022 they published an article in ‘Nature’ in which they described an enigmatic transient object that appeared and disappeared intermittently, emitting powerful beams of energy three times an hour. Dr. Hurley recalls that the first object took them by surprise. “We were stumped,” he says. “So we started looking for similar objects to find out if it was an isolated event or just the tip of the iceberg.”“.
Between July and September 2022, the team scanned the skies using the MWA telescope. They soon found what they were looking for in GPM J1839-10, which emits bursts of energy that last up to five minutes, five times longer than the first object.
Other telescopes followed up to confirm the discovery and learn more about the object’s unique features. These include three CSIRO radio telescopes in Australia, the MeerKAT radio telescope in South Africa, the 10-m Grantecan (GTC) telescope, and the XMM-Newton space telescope.
Armed with the coordinates and celestial features of GPM J1839-10, the team also began searching the observational archives of the world’s leading radio telescopes. “It appeared in observations from the Giant MW Radio Telescope (GMRT) in India, and the US Very Large Array (VLA) had observations going back to 1988.” Explain.
“It was an incredible moment for me,” he says. “I was five years old when our telescopes first recorded the impulses of 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.”
Not all magnetars produce radio waves. Some exist below the “line of death,” a critical threshold at which a star’s magnetic field becomes too weak to generate high-energy emissions.
“The object we have discovered rotates too slowly to produce radio waves: it is below the line of death Hurley-Walker explains. Assuming it is a magnetar, it should not be possible for this object to produce radio waves. But we are seeing them, and we’re not just talking about a little radio broadcast. Every 22 minutes, it emits a five-minute pulse of radio-wavelength energy, and it’s been doing that for at least 33 years. Whatever the mechanism behind this is extraordinary“, he assures.
The discovery has important implications for our understanding of the physics of neutron stars and the behavior of magnetic fields in extreme environments. It also raises new questions about the formation and evolution of magnetars and it could shed light on the origin of mysterious phenomena like fast radio bursts.
The team of researchers plans to carry out new observations of the magnetar to better understand its properties and behavior. They also hope to discover more of these enigmatic objects in the future, to determine whether they are indeed ultra-long-lived magnetars or something even more phenomenal.
The MWA is the forerunner of the world’s largest radio astronomy observatory, the Square Kilometer Array, which is being built in Australia and South Africa. The MWA celebrates a major milestone this year as it marks a decade of international scientific discoveries and operations.
