Astronomers from the University of Sydney have discovered a mysterious source of radio signals. Analysis has so far failed to uncover the origin of the source, which has been dubbed ASKAP J173608.2-321635, a report in Science Alert reveals.
In a paper available on preprint server arXiv, the researchers describe the mysterious object as "a highly-polarized, variable radio source located near the Galactic Center and with no clear multi-wavelength counterpart."
"ASKAP J173608.2-321635 may represent part of a new class of objects being discovered through radio imaging surveys," they continue.
The researchers discovered the mysterious source of radio signals while analyzing data from the Australian Square Kilometre Array Pathfinder (ASKAP), which was specifically designed to pick up radio signals from the depths of the universe. Short bursts of radio waves, known as radio transients often signal unusual astronomical events. In fact, just last week a study revealed that a mysterious source of radio waves discovered in 2017 came from a never-before-seen premature supernova triggered by a nearby black hole.
Mysterious celestial object highlights need for higher survey cadence
Though further analysis might reveal that ASKAP J173608.2-32163 is, in fact, a known object, new data provided by the strong radio waves could reveal a great deal about that object. The researchers say that the object is highly variable as it emits radio waves for up to weeks at a time before suddenly disappearing for up to three months.
ASKAP J173608.2-32163 was first observed in April 2019 when the AKAP array picked it up as it searched for radio transients. Between April of 2019 and August 2020, the same object was detected 13 times. It was later also detected by the MeerKAT radio telescope in South Africa in February 2021 and by the Australia Telescope Compact Array (ATCA) in April 2021. The source is surprisingly elusive, as it hasn't made an appearance in any X-ray and near-infrared observations, or in archives of old radio data checked by the University of Sydney researchers. This means it could not be a supernova, a pulsar, or a flaring star, all objects that were originally considered to be the source.
The object does share some properties with mysterious signals spotted near the center of the galaxy, known as Galactic Center Radio Transients (GCRT). Three of these were spotted in the early 2000s and the astronomical community has yet to find an explanation for the objects. The researchers say that future observations will allow a greater understanding of how common GCRT's and objects such as ASKAP J173608.2-32163 truly are. According to the researchers, "increasing the survey cadence and comparing the results of this search to other regions will help [them] understand how truly unique ASKAP J173608.2-321635 is and whether it is related to the Galactic plane, which should ultimately help us deduce its nature."