PSR J0523-7125, a highly circularly polarized, variable, steep-spectrum pulsar located in the Large Magellanic Cloud, is the brightest extragalactic pulsar known, and it could even be the most luminous one ever found.
A section of the Large Magellanic Cloud, captured under normal conditions by SARAO’s MeerKAT radio telescope. It is detecting all radio light, and PSR J0523-7125 looks like just another source of radio light. Image credit: Yuanming Wang.
Pulsars offer astrophysicists potential applications in areas like random number generation and guidance systems for spacecraft.
These objects are rapidly rotating neutron stars that emit two beams of polarized radio light.
As the beams flash across space they create a unique timing and polarization signature.
Traditional methods of finding pulsars look for this flickering in telescope data but can miss those that are too fast or too slow.
By looking instead for light that is polarized, pulsars outside the standard timing range can be found.
As part of the Australian Square Kilometre Array Pathfinder (ASKAP) Variables and Slow Transients (VAST) survey, CSIRO researcher Yuanming Wang and her colleagues used the ASKAP radio telescope to apply their new method of seeking out pulsars.
By using the astronomical version of ‘sunglasses’ to capture light that is polarized, they spotted PSR J0523-7125, a never-before seen pulsar that is 10 times brighter than any other detected outside our Milky Way Galaxy.
“This was an amazing surprise,” said Wang, who is also a Ph.D. candidate at the University of Sydney.
“I didn’t expect to find a new pulsar, let alone the brightest.”
“But with the new telescopes we now have access to, like ASKAP and its sunglasses, it really is possible.”
The astronomers then confirmed their discovery with SARAO’s MeerKAT radio telescope.
“We should expect to find more pulsars using this technique,” said Professor Tara Murphy, an astronomer with the Sydney Institute for Astronomy at the University of Sydney.
“This is the first time we have been able to search for a pulsar’s polarization in a systematic and routine way.”
“Because of its unusual properties, this pulsar was missed by previous studies, despite how bright it is.”
“It is incredible that the first pulsar to be found using this technique is an extreme one,” added Professor Elaine Sadler, chief scientist of CSIRO’s Australia Telescope National Facility.
“This speaks to all the great things we can expect from our telescopes and researchers as they constantly find new ways to answer some of our biggest questions.”
The discovery of PSR J0523-7125 is described in a paper published in the May 1, 2022 issue of the Astrophysical Journal.
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Yuanming Wang et al. 2022. Discovery of PSR J0523-7125 as a Circularly Polarized Variable Radio Source in the Large Magellanic Cloud. ApJ 930, 38; doi: 10.3847/1538-4357/ac61dc
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