by Simon Mansfield
Sydney, Australia (SPX) Jul 02, 2025
Observations of pulsars-spinning neutron stars with immense magnetic fields-are proving vital in preparing the SKA Observatory for early science operations. A recent release features data from an early build of the SKA-Low telescope, now under construction in Western Australia.
Known for their regular radio pulses, pulsars act as remarkably precise celestial clocks, with accuracy rivaling atomic clocks on Earth. One such object, the Vela pulsar, lies about 900 light years from Earth and is among the brightest in the Southern sky. It is also one of nearly 50 pulsars studied so far during the commissioning of SKA-Low, which sits on Wajarri Yamaji Country.
"SKA-Low is a hugely complex scientific instrument-you can't just plug it in and expect everything to work perfectly. By comparing our pulsar observations with existing data, we can make sure the system is working as intended, and fine-tune it where needed," said Dr Shivani Bhandari, SKA-Low Commissioning Scientist.
The featured Vela pulsar observation used four complete SKA-Low stations, each made up of 256 two-meter-tall antennas, totaling 1,024 antennas. Teams are calibrating each station as it comes online, ensuring they function together as a cohesive telescope array.
"These observations are a vital part of the commissioning process because they allow us to test the sensitivity of each station as it comes online," added Dr Bhandari.
These efforts are part of preparing the telescope for early science use by 2027. During the upcoming "science verification" phase, researchers will be able to propose observations using the still-growing array to help optimize performance ahead of future scientific campaigns.
"The science capability of this very flexible telescope is being tested through the overall Science Commissioning programme. In addition to pulsar observations, we are also using the telescope in its imaging mode to observe radio emission from distant galaxies containing supermassive black holes..." explained Dr George Heald, SKA-Low Lead Commissioning Scientist. "As the telescope increases in scale, our commissioning tests will also get more complex and lead to the validation of specific observing modes for use in the Science Verification process."
Meanwhile, construction on both SKA-Low and SKA-Mid continues at pace. Over 6,400 antennas have been installed in Australia-about 5% of the final SKA-Low configuration of 131,072 antennas spanning 74 kilometers. In South Africa, 50+ dish foundations for the SKA-Mid array are complete, joining the already-operational MeerKAT telescope.
Hardware for both arrays is sourced internationally. Italy manufactures antennas and processing boards, while the UK supplies low-noise amplifiers. Initial data processing racks are already being installed at the Pawsey Supercomputing Research Centre in Perth.
Pulsars, like Vela, emit beams of radio waves detectable from Earth and serve as laboratories for extreme physics, including tests of General Relativity. The SKA telescopes will time millisecond pulsars with extraordinary precision-better than one ten-millionth of a second-to detect subtle effects such as gravitational waves rippling through our galaxy.
The Vela pulsar originated roughly 12,000 years ago from a supernova explosion. The event produced a dense neutron star the size of a city but with up to twice the mass of the Sun, spinning 11 times each second.
Related Links
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