Why in news?
A team using the Southern‑sky MWA Rapid Two‑Metre (SMART) survey has detected a new millisecond pulsar in our Galaxy. The pulsar, known as PSR J0125‑5854, spins once every 24.6 milliseconds and lies about 1,600–3,200 light‑years away. This is the first time the low‑frequency Murchison Widefield Array (MWA) has discovered such a fast pulsar, and the find highlights the telescope’s wide field of view and the promise of future SKA‑Low surveys.
Background
The MWA is a radio telescope located in Western Australia. It operates at low frequencies between 80 and 300 MHz. The array is one of the precursor instruments for the upcoming Square Kilometre Array (SKA) Low telescope. Its design uses thousands of small antennas spread over several kilometres. This gives it a very wide field of view and good sensitivity. In 2022 scientists proposed the SMART survey to scan the entire southern sky with the MWA. The survey observes each patch of sky for about 80 minutes. This long integration allows astronomers to search for faint radio pulses from rotating neutron stars. The SMART team expects to find hundreds of new pulsars.
Key findings from the discovery
- New millisecond pulsar: PSR J0125‑5854 is a fast‑spinning neutron star with a period of 24.6 ms. Its radio pulses were detected during a short test scan of the SMART survey. The pulsar’s dispersion measure suggests it lies roughly 1,600–3,200 light‑years away from Earth.
- Binary system: Timing follow‑up shows that the pulsar is in a wide binary system. It orbits its companion every 833 days with a minimum companion mass of about 0.4 solar masses.
- SMART survey design: The survey uses the MWA’s wide field of view of about 610 square degrees to cover the entire southern sky in about 70 sessions. Each session produces large volumes of data but can detect weak pulsar signals.
- Preparation for SKA‑Low: The upcoming SKA‑Low telescope, being built in Australia, will consist of more than 131,000 antennas to observe frequencies between 50 and 350 MHz. Discoveries like PSR J0125‑5854 help scientists develop techniques for the next‑generation telescope.
Significance
Pulsars are dense stellar remnants that spin rapidly and emit radio beams. Millisecond pulsars are especially important because their stable spin rates make them precise cosmic clocks. The discovery of PSR J0125‑5854 proves that low‑frequency telescopes like the MWA can find such objects. The SMART survey will enlarge the known pulsar population and help test theories of gravity and matter under extreme conditions. It also serves as a pathfinder for the SKA‑Low, which will be the world’s largest radio telescope.
Conclusion
The first millisecond pulsar discovered by the SMART survey is an encouraging milestone. It shows that wide‑field surveys with the Murchison Widefield Array can uncover hidden neutron stars. Future observations with the SKA‑Low should reveal many more pulsars and deepen our understanding of the Universe.
Sources: Phys.org