Researchers find 44-minute repeating radio signal

On May 28, 2025, astronomers said they had found a Milky Way object that emits radio waves and X-rays in lockstep every 44.2 minutes. The source, ASKAP J1832-0911, was detected with the Australian Square Kilometre Array Pathfinder radio telescope and NASA’s Chandra X-ray Observatory, according to a paper in *Nature* and statements from NASA, Chandra and the International Centre for Radio Astronomy Research. The object sits about 15,000 light-years from Earth and produces pulses lasting roughly two minutes in each cycle, ICRAR and Curtin University said. Researchers classified it as a long-period radio transient, a category only identified in 2022 and still not well explained. ### Why are astronomers paying attention to a 44-minute cycle? The 44.2-minute period is unusually slow for an object that behaves like a compact radio beacon. (nature.com) NASA said the cycle is thousands of times longer than the repeated variations seen in ordinary pulsars, which can flash multiple times each second. Long-period radio transients already stood out because they repeat on timescales of minutes to hours rather than milliseconds or seconds. (icrar.org) Earlier work had identified other long-period sources, including one active for decades and another with a 54-minute period, but ASKAP J1832-0911 added a new feature: synchronized X-ray emission. ### What exactly did the team detect? The *Nature* paper reported ASKAP J1832-0911 as an “extremely bright” long-period radio transient with radio and X-ray emission sharing the same 44.2-minute period. (nasa.gov) NASA’s Chandra team said this was the first time an X-ray signal had been found from a long-period radio transient. The ASKAP telescope first identified the source in radio data from Wajarri Country in Australia, according to ICRAR and CSIRO-linked materials. (nature.com) Chandra then caught the source while it was in an X-ray-bright state, letting researchers compare the two bands directly. ### Is this the same thing as a fast radio burst? Fast radio bursts are usually millisecond-duration events and are generally discussed as a different phenomenon. (nature.com) A recent *Nature Astronomy* overview described FRBs as a separate field with burst timescales far shorter than the minutes-long behavior seen in long-period transients. ASKAP J1832-0911 therefore is not notable because it extends known FRB timing by a factor of a few. (icrar.org) It belongs to a different observational class altogether: repeating Galactic long-period transients with cycles measured in tens of minutes. ### What do researchers think the object might be? The leading ideas cited by NASA, ICRAR and related summaries include a highly magnetized neutron star, sometimes described as a magnetar, or a white-dwarf-based system. (nature.com) None of those models fully explains all of the observed properties, the institutions said. A separate arXiv study on a 44-minute periodic radio transient in a supernova remnant said such sources may support a neutron-star origin in at least some cases. (nature.com) That paper referred to the same direction on the sky as ASKAP J1832-0911 and said the astrophysical nature of long-period transients remains undetermined. ### What happens next? The May 28, 2025 paper gave astronomers a target for more coordinated monitoring in radio and X-rays. (icrar.org) Future observations will look for changes in brightness, polarization, environment and any companion object that could distinguish between a neutron star, a white dwarf binary, or another explanation. ASKAP J1832-0911 is now one of the clearest test cases in the long-period transient class because it combines a measured 44.2-minute cycle with matched X-ray and radio pulses. (arxiv.org) That combination is where follow-up campaigns are likely to focus. (chandra.si.edu) (nature.com)