This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Astronomers have detected extreme, never-before-seen behavior from a rare kind of pulsar and stumbled on a surprising link to one of astronomy's biggest current mysteries. Using 174 hours of radio observations, researchers detected PSR J1227-4853, a rapidly spinning neutron star known as a "transitional millisecond pulsar," which unleashes hundreds of ultrashort, ultrapowerful "giant pulses." Their paper was published in The Astrophysical Journal on July 31.
Neutron stars that rapidly rotate, completing one rotation in less than about 30 milliseconds, are called millisecond pulsars (MSPs). Among them is a rare class of neutron stars called transitional millisecond pulsars that swing between two different observational states: an accretion-powered state in a low-mass X-ray binary system and a radio-powered millisecond pulsar state. So far, only three transitional MSPs have been confirmed to exhibit this switching behavior.
In this study, Saptarshi Sarkar of the National Center for Radio Astrophysics in India and colleagues studied the third of these confirmed systems, PSR J1227−4853. Discovered in 2014 using the Giant Metrewave Radio Telescope (GMRT), it completes one rotation every 1.69 milliseconds. What made it an exciting target was its unusually strong magnetic field at the pulsar's "light cylinder"—an imaginary cylinder centered on the pulsar with a radius at which material co-rotating with the star's spin would have to move at the speed of light.
It also showed a high spin-down luminosity, which is the rate of its kinetic-energy loss as its rotation slows down. These properties are linked to a rare phenomenon called giant pulses (GPs)—extremely brief, extraordinarily bright radio flashes reaching up to 10,000 times brighter than the pulsar's normal signal. To date, only 19 pulsars have been found that produced them.
None of the transitional millisecond pulsars have shown this behavior, so the team was motivated to check whether this rare pulsar also produces such giant pulses. The team combined two datasets from the upgraded GMRT: a larger set spanning about 165 hours over five years and a smaller, higher-resolution follow-up set spanning nine hours of observations taken over less than six months. After carefully filtering out radio interference, they confirmed 235 genuine giant pulses, some lasting barely over a millionth of a second.
The pulses were found to be produced from two "hot spots" in the pulsar's spin cycle. Notably, none were found in a separate region where some other giant-pulse-emitting pulsars do show activity. This shows that the emission is not random and comes from a highly localized region of the pulsar's magnetic environment.
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