Astronomers have discovered something in the center of the Milky Way galaxy that has left them baffled. The team has detected a repeating radio signal near the center of our galaxy that they say is unlike any radio signal seen before. Researchers are sure the radio signal isn’t a fast radio burst, a pulsar, or a low-mass star.
While they know what the signal isn’t, what it is, they don’t know. The mysterious radio signal is strange in that it sometimes appears very bright in the radio spectrum for weeks and then will completely disappear within the span of the day. Astronomers say its behavior doesn’t fit any known profile for types of celestial bodies. They believe the mysterious radio signal’s source could represent a new class of objects discovered via radio imaging.
The object creating the radio signal is called ASKAP J173608.2−321635 and was discovered by radio astronomers using the Australian Square Kilometer Array Pathfinder (ASKAP). The bizarre signal was discovered in an ASKAP survey that was conducted from April 2019 through August 2020.
In that survey, the signal appeared 13 times and never lasted more than a few weeks per occurrence. One of the oddities about the radio signal is that it has no predictable pattern, seemingly appearing and disappearing at random. Another oddity is that the signal has appeared in no data collected by other radio telescopes before this survey.
Another big mystery is the fact that astronomers attempted to observe the object using other telescopes, including the Chandra X-ray Observatory and the Swift Observatory, along with other instruments. However, when the object was viewed with these other telescopes capable of picking up near-infrared wavelengths, the signal disappeared completely. ASKAP J173608.2−321635 appears to have no emissions across any other portions of the electromagnetic spectrum.
Astronomers believe the closest match to what they’re seeing is a type of object known as a galactic center radio transient. Only three of those objects have been detected so far, and if this signal is a galactic center radio transient, it will change theories on what the objects are capable of.