Strange Radio Waves Emerge From The Milky Way

Astronomers discovered unusual signals that were coming from the center of Milky Way. These radio waves are not consistent with any known variable radio source patterns and could indicate a new class or stellar object.

“The most remarkable property of this signal is its high polarization. It means that the light oscillates only in one direction but the direction it rotates over time,” Ziteng Wang, the lead author of the study and a doctoral candidate at the Faculty of Physics, University of Sydney, explains.

“The brightness of the object also changes dramatically, by a factor 100, and the signal switches on and off almost randomly. He adds that we have never seen anything similar.

These radio waves have some similarities to another class of mysterious objects, known as radio transients in the galactic centre. One such object is called a “cosmic burper”.

Numerous stars emit different light across the electromagnetic spectrum. The study of transient or variable objects in radio waves, a vast field of research that has been made possible by radio astronomy advances, is an important part of our understanding of the Universe. There are many types of astronomical objects with brightness that varies, including the supernovae, the pulsar, and stars burning.

It could have been a pulsar or a dense type of spinning star, or even a star that emits large solar flares. Wang says that the signals coming from this source are not consistent with what we would expect from this type celestial object.

Yesterday’s publication in The Astrophysical Journal reported the discovery of the object.

Wang was joined by a team of international scientists, which included scientists from Australia CSIRO, USA, Canada and South Africa. They discovered the object with the radio telescope ASKAP at CSIRO in Western Australia. Follow-up observations were made using the MeerKAT telescope from the South African Radio Astronomy Observatory.

Mr. Wang is supervised by Professor Tara Murphy, who also works at the School of Physics and the Sydney Institute of Astronomy.

Professor Murphy stated that “We have been looking at the sky with ASKAP in order to find unusual objects. This project is called Variables and Slow Transients, (VAST), and will continue to do so throughout 2020 and 2021.” We found ASKAP J173608 at the center of our galaxy.2-321635 was its name. The uniqueness of this object was that it appeared to be invisible at first, then became brighter, faded and returned to its original form. This was a remarkable behavior.

“The source vanished in one day even though it was present for several weeks in previous ASKAP observations.”

Astronomers attempted to locate the object in visible sunlight after detecting six radio signals over nine months. They couldn’t find it. They tried again with the Parkes radio telescope, but this time they couldn’t find the source.

Professor Murphy says, “We then tested the most sensitive MeerKAT radar telescope in South Africa.” We watched the signal for fifteen minutes every few weeks to try and see if it would return. The signal returned but the behavior of our source was drastically different. It disappeared in one day, despite having been present for several weeks in previous ASKAP observations.

However, this discovery didn’t reveal any more information about this transient radio source.

They will be more attentive to this object

Wang’s codirector, Professor David Kaplan of University of Wisconsin-Milwaukee, insists that the “information we have has some similarities with another emerging class of mystery objects known as radio transients of galactic center”, including the ‘cosmicburper. ‘ Our new object, ASKAPJ173608.2-321635 shares some properties with the GCRTs but there are also differences. We don’t know the sources, so this only adds to the mystery.

Scientists plan to monitor the object closely for further clues.

“In the next decade, Square Kilometer Array (SKA), a transcontinental radio telescope, will be available online. Professor Murphy concludes that you will be able make sensitive maps of our sky each day. We hope the telescope’s power will allow us to solve more mysteries such as this one, but it will also make the cosmos much more accessible for radio-frequency exploration.