Scientists catch strange signals from the center of the Milky Way

Scientists find strange radio waves, unlike anything seen before, originating from the center of the Milky Way.

According to the journal Skyatnight, the team caught the strange signal using the Australian Square Kilometer Array Pathfinder (ASKAP), a radio telescope located at the Murchison Observatory (Australia).

Ziteng Wang, a PhD student at the University of Sydney, said the signal was recorded as early as 2020, via ASKAP. He and his team of astronomers set out to find sources of radio waves that frequently turn on, off, or change in brightness.

The ASKAP telescope at the Murchison Observatory has detected a strange signal from the center of the Milky Way.

As they explored towards the center of the Milky Way, they detected a new signal and named it ASKAP J173608.2-321635.

The strangest aspect of this radio source is its high polarizability. Our eyes cannot distinguish between circularly polarized and unpolarized light, but ASKAP has filtering capabilities, similar to polarized sunglasses.

"These types of broadcast sources are very rare, often in each observation, out of thousands of sources, we find only 10 sources that are polarized," Wang said.

In addition, ASKAP J173608.2-321635 is special because the broadcast source turns on and off abnormally. It may flash and then fade within a day, but the change sometimes lasts several weeks.

Regarding the origin, scientists have not found a satisfactory answer. Initially, Wang's team thought it was coming from a star because of the same characteristics of frequent switching on and off and polarization of the signal.

However, this new source is very different from the stars, which do not have any signals in infrared and it is too bright compared to normal. The team also thinks that the radio waves come from a pulsar or a burning star, but there is no reliable evidence yet.

Wang and colleagues used other methods to trace the source of ASKAP J173608.2-321635, including the Parkes radio telescope to find the short pulse, to determine if it was a pulsar. Are not.

They learned about this signal at X-ray wavelengths through the Neil Gehrels and Chandra Observatory. In parallel, the team used the Gemini telescope to track infrared waves. However, all of them found nothing more.

ASKAP J173608.2-321635 shares some similarities with GCRT - variable radio waves were detected near the center of the Milky Way, the origin of which remains a mystery. GCRT appears acyclic, highly polarized, and does not include X-rays or optics.

But in terms of operation time, the signal just found is not similar to the GCRTs recorded before, so nothing can be concluded.

Scientists will continue to monitor the radio waves of ASKAP J173608.2-321635 for a longer time to determine the detailed spectral characteristics. However, they still do not know when it will reappear.

With more observations, scientists could learn how the signal works, its flash period and its origin.