Scientists Discover Strange Radio Waves Unlike Anything Previously Detected, Originating from the Center of the Milky Way.
According to the magazine Skyatnight, the research team captured the unusual signal using the Australian Square Kilometre Array Pathfinder (ASKAP), a radio telescope located at the Murchison Observatory in Australia.
Ziteng Wang, a PhD candidate at the University of Sydney, noted that the signal was recorded from early 2020 through ASKAP. He and his team of astronomers were conducting a search for radio sources that regularly turn on and off or change in brightness.
The ASKAP telescope at Murchison Observatory detected the strange signal from the center of the Milky Way. (Photo: CSIRO).
While exploring towards the center of the Milky Way, they discovered a new signal and named it ASKAP J173608.2-321635.
The most peculiar aspect of this radio source is its high polarization. Our eyes cannot distinguish between circularly polarized light and unpolarized light, but ASKAP has the ability to filter, similar to polarized sunglasses.
“Such types of radio sources are very rare; typically, in every observation, among thousands of sources, we only find 10 that are polarized,” Wang stated.
Additionally, ASKAP J173608.2-321635 is unique because the radio source exhibits unusual on-off behavior. It can flare up and then gradually fade within a day, but the changes sometimes last for weeks.
Regarding its origin, scientists have not yet found a satisfactory answer. Initially, Wang’s team thought it might be emanating from a star due to its similar characteristics of regular on-off behavior and polarized signals.
However, this new source significantly differs from stars, showing no signals in the infrared spectrum and being much brighter than normal. The research team also considered the possibility that the radio waves could originate from a pulsar or a burning star, but no reliable evidence has been found.
Wang and his colleagues employed additional methods to trace the source of ASKAP J173608.2-321635, including the Parkes radio telescope to search for short pulses to determine if it is a pulsar.
They also investigated this signal at X-ray wavelengths using the Neil Gehrels and Chandra Observatories. Simultaneously, the team used the Gemini telescope to search for infrared signals. However, none of these efforts yielded additional findings.
ASKAP J173608.2-321635 has some similarities with GCRT – variable radio waves detected near the center of the Milky Way, whose origins remain a mystery. GCRT appears sporadically, is highly polarized, and does not accompany X-ray or optical signals.
However, in terms of operational timing, the newly found signal does not resemble previously recorded GCRTs, so no conclusions can yet be drawn.
Scientists will continue to monitor the radio waves of ASKAP J173608.2-321635 over a longer period to determine detailed spectral characteristics. However, they are still unsure when it will appear again.
If more observations are made, scientists may be able to understand how the signal operates, its flashing cycle, and its origins.
