The Parkes Radio Telescope, located in New South Wales, Australia (also known as Murriyang), detected unusual radio pulses from the previously dormant magnetar XTE J1810-197, which has an extremely strong magnetic field.
A new paper published on April 8th in Nature Astronomy provides detailed descriptions of this phenomenon.
People's Impressions of Magnetars
Image Source: Carl Knox, OzGrav/Swinburne University
The Parkes radio telescope (also known as Murriyang) Image Source: Alex Cherney / CSIRO
Magnetars are a type of neutron star with extremely strong magnetic fields, more than a trillion times stronger than Earth's or the Sun's.
XTE J1810-197, located 8000 light-years away from Earth, is currently the closest known magnetar to our planet. Discovered in 2003, it remained dormant for over a decade until it reappeared in data from the Lovell Telescope at the University of Manchester in 2018.
While most magnetars are known to emit linearly polarized light, the light from XTE J1810-197 is circularly polarized, indicating a spiral pattern as it traverses the cosmos.
"Unlike the radio signals we've seen from other magnetars, this one is emitting a lot of rapidly changing circularly polarized light. We've never seen anything like it before," says Marcus Lower, a postdoctoral researcher at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the lead author of the paper.
Radio signals from magnetars themselves are extremely rare, but those received from XTE J1810-197 are unprecedented, showcasing a level of complexity not previously observed in these celestial objects.
"The signals from this magnetar suggest that the interactions on the star's surface are more complex than previous theoretical explanations," says Manisha Caleb, a doctoral candidate at the University of Sydney and a co-author of the paper.
What could be causing these signals remains uncertain, but the team has a hypothesis.
"Our findings suggest that there's an overheated plasma above the magnetic poles of the magnetar, acting like a polarizing filter. How exactly the plasma accomplishes this remains to be determined," explains Lower.
Magnetars stand as some of the most enigmatic objects in the universe. Understanding them can shed light on other extreme and unusual phenomena, such as plasma dynamics, X-ray and gamma-ray bursts, and even mysterious fast radio bursts.
For more information, refer to the related paper: https://doi.org/10.1038/s41550-024-02225-8
