A recent discovery by researchers using the CSIRO's Murriyang radio telescope, located in Parkes, marks a turning point in our understanding of neutron stars, especially magnetars. These celestial bodies, known to be the most powerful magnets in the Universe, have revealed unexpected characteristics, opening new avenues in the study of extreme astrophysical phenomena.
Artist's impression of a magnetar with a powerful magnetic field.
Credit: CSIRO
At the heart of this discovery is the magnetar XTE J1810-197. Located about 8,000 light-years from Earth, it emitted radio pulses with circular polarization, a property where light seems to spiral through space. This feature defies previous theoretical explanations and suggests complex interactions on the star's surface.
The results of this research, published in the journal
Nature Astronomy, highlight the unique behavior of XTE J1810-197. Unlike the radio signals usually observed for other magnetars, those emitted by XTE J1810-197 exhibit rapid changes in their circular polarization, a first in the field of astrophysics.
After a silence of more than a decade, the signals from XTE J1810-197 were detected anew in 2018 by the University of Manchester's Lovell telescope and then observed in detail by Murriyang. Thanks to its ultra-wideband receiver, this telescope played a crucial role in tracking the radio emissions of the magnetar, allowing precise measurements of its unique features.
Artist's impression of a magnetar.
Credit: Carl Knox, OzGrav The researchers, led by Dr. Marcus Lower of CSIRO, suggest that the presence of superheated plasma above the magnetar's magnetic pole could act as a polarizing filter, thus affecting the nature of the radio waves emitted. This hypothesis raises questions about how plasma influences these signals, a mystery that the team hopes to solve in the future.
The discovery not only reveals unexplored aspects of magnetars but also offers insights into phenomena such as plasma dynamics, X-ray and gamma-ray bursts, and fast radio bursts. It underscores the importance of technological advances in radio astronomy, particularly the development of ultra-wideband receivers, which open new windows onto the Universe.
This research contributes to broadening our understanding of the physical laws governing extreme astrophysical environments and highlights the crucial role of terrestrial observations in exploring the distant Universe.