A strange radio signal emanating from a location 15,000 light-years away could indicate an as-yet-unconfirmed type of star. Called GPM J1839-10, this particular cosmic object was discovered to emit radio waves every 22 minutes. This speed is extremely slow compared to other pulsed radio wave sources. Furthermore, a careful analysis of archival information shows that we have been recording its slow heartbeat for more than 30 years. Until now, this has escaped our attention. According to a team led by astrophysicist Natasha Hurley-Walker from the Curtin University node of the International Center for Radio Astronomy Research (ICRAR) in Australia, the most likely explanation is that the source is a magnetar. has a very slow rotation speed. If so, it would go against our understanding of these wild star corpses, meaning something strange is going on. “This remarkable object challenges our understanding of neutron stars and magnetars, which are among the strangest and most extreme objects in the Universe,” Hurley-Walker said. Artist’s impression of the Murchison Widelfield Array observing GPM J1839-10. (ICRAR)This discovery comes after a similar object was discovered in the Milky Way three years ago in archival data, as published in a 2022 paper.

Called GLEAM-X J162759.5−523504.3, it was recorded emitting radio waves for about a minute, every 18 minutes, although it fell silent in 2018 and has not been heard from since. From the way the light is twisted, it appears that it comes to us through a highly magnetic medium. Hurley-Walker and his team wanted to see if they could find other objects with similar behavior. So they took observations of the southern sky using the Murchison Widefield Array in Australia to conduct the survey. They found an object emitting five-minute bursts of radio light every 22 minutes. They aimed other telescopes at its coordinates and looked through the site’s archived data. The new observations allowed them to characterize the radio emission in detail, showing similar variations suggestive of modification by magnetic fields. And archival data shows that GPM J1839-10 has been detecting pulses since at least 1988. “I was 5 years old when our telescope first recorded pulses from this object, but no one paid attention to it and it remained hidden in the data for 33 years,” Hurley-Walker said.

“They missed out because they didn’t expect to find something like this.” Infographic of all observatories that have observed GPM J1839-10. (SARAO; Daniel López/IAC; Marianne Annereau; NCRA; CSIRO/Dragonfly Media; AUI/NRAO; ESA) The light profile is very similar to magnet pulses. It is a type of neutron star – a remnant of the collapsed core of a massive star that goes supernova after burning its thermonuclear fuel – with an extremely strong magnetic field. But the strength of this magnetic field is correlated with the rotation period of the magnet. The strength of the magnetic field must be above a certain threshold, called the dead line, to produce powerful radio radiation. There’s a good reason why no one expected to find something like GPM J1839-10.

“The object we detected is spinning too slowly to produce radio waves – it is below the boundary of death,” Hurley-Walker said. “Assuming it was a magnet, this object could not have produced radio waves. But we saw them. And we’re not just talking about a small radio broadcast signal. Over the course of 22 minutes, it emitted emits 5-minute radio pulses.” wavelength energy, and has been doing so for at least 33 years. The mechanism behind this is extraordinary. »The study was published in the journal Nature.

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