Astronomers from Australia have recorded a unique radio signal.
Astronomers from Australia have discovered a mysterious repeating radio signal near the center of the Milky Way. This is reported by the Live Science portal with a link to an article hosted on the arXiv preprint server.
What is known about this radio signal?
The radio source was named ASKAP J173608.2-321635. Between April 2019 and August 2020, the cryptic signal appeared 13 times, and it never lasted more than a few weeks. The detected radio source appeared and disappeared without any regularity. Earlier radio telescopes did not record it. Scientists described the signal as “a highly polarized variable radio source located close to the galactic center and has no clear multi-wavelength analogue.”
Astronomers note that the radio signal is easily detected in the radio frequency spectrum for several weeks, and then it completely disappears in a day. This behavior is unique to all celestial bodies known to date. Therefore, the researchers believe that they can deal with “a new class of objects detected using radio images.”
“The most amazing property of this source is that it is highly polarized. Our eye cannot distinguish between circularly polarized light and unpolarized light, but ASKAP has the equivalent of polarized sunglasses to filter it out. Such sources are really rare, we usually find no more than 10 out of thousands of sources in one observation, “- the lead author of the study, Ziteng Wang, told New Atlas. He added that the found radio signal source unexpectedly turns on and off. “The brightness of this source can change dramatically, decreasing in one day. But sometimes it can last for several weeks, ”the researcher explained.
In February 2021, a mysterious radio signal was also detected by the MeerKAT radio telescope in South Africa, and in April by the Australian ATCA telescope. Previously, it was not detected either in X-rays or in observations in the near infrared range.
According to scientists, they could detect the so-called radio transient towards the center of the Galaxy (GCRT). “Since the source is close to the Galactic Center, this source could be the new GCRT. However, the burst timeline from our source is inconsistent with the GCRT timeline. In addition, they are detected at lower frequencies, ”said Wang. At the same time, the researchers note that not much is known about the GCRTs themselves.
How did you find the radio signal?
ASKAP J173608.2-32163 was detected using the Australian Square Kilometer Array Pathfinder radio telescope (ASKAP). It is one of the most sensitive radio telescopes in the world. It is located at the Murchison Observatory in western Australia. The telescope scans the sky looking for incoming and outgoing radio sources that may be associated with pulsars, magnetars, supernovae, stellar flares, etc.
The signal was first acquired in April 2019 as part of the Variable and Slow Transient Study (VAST).