Astronomers have discovered unusual signals from the center of the Milky Way.
These are radio waves that do not fit any pattern currently understood from variable radio source and could suggest a new kind of stellar object, as they publish in the magazine Astrophysical Journal.
“The strangest property of this new signal is that it has a very high polarization. This means that its light ranges in a single direction, but that direction revolves over time – explains Ziteng Wang, main author of the new study and doctorate student in
The Physics School of the University of Sydney, in Australia -. The brightness of the object also varies drastically, by a factor of 100, and the signal is turned on and off apparently at random. We have never seen anything similar, “he admits.
Many types of stars emit variable light throughout the electromagnetic spectrum.
With the enormous advances in radio astronomy, the study of variable or transient objects in radio waves is a huge field of study that helps us reveal the secrets of the universe.
Pulsares, supernovas, stars that shoot and fast radio bursts are all types of astronomical objects whose brightness varies.
“At first we thought it could be a pulsar-a kind of dead star very dense that turns- or a kind of star that emits huge solar flares. But the signs of this new source do not match what we expect from this type of objects
Celesties, “he recalls.
Wang and an international team formed by scientists from the Australian national scientific agency CSIRO, Germany, the United States, Canada, South Africa, Spain and France, discovered the object using the Askap radiotelescope of CSIRO in Western Australia.
Subsequent observations were made with the Meerkat telescope of the South African radio astronomy observatory.
The Wang Doctorate Supervisor, Professor Tara Murphy, also from the Sydney Institute of Astronomy and the Faculty of Physics, explains that they have been watching the sky with Askap to find new unusual objects with a project known as variables and slow transients (
Vast), along 2020 and 2021.
“Looking towards the center of the Galaxy, we find Askap J173608.2-321635, so called by its coordinates – I laughed. This object was unique, as it began being invisible, it became bright, it faded and then reappeared. This behavior was
extraordinary”.
After detecting six radio signals from the source for nine months in 2020, astronomers tried to find the object in visual light, but they did not find anything.
Then resorted to the Parkes radiotelescope but again they did not detect the source.
Murphy explains that then tested with the Meerkat radiotelescope, more sensitive, located in South Africa.
“As the signal was intermittent, we observed it for 15 minutes every few weeks, hoping to see her again – remember– Luckily, the signal returned, but we discovered that the behavior of the source was drastically different: the source
He disappeared in a single day, although he had lasted weeks in our previous observations of Askap. ”
However, this new discovery did not reveal much more about the secrets of this transient radio source.
The Wang co-supervisor, Professor David Kaplan from the University of Wisconsin-Milwaukee, notes that “the information obtained has some parallels with another emerging class of mysterious objects known as radio transients of the Galactic Center, including one nicknamed the ‘outbreak
cosmic'”.
“Although our new object, Askap J173608.2-321635, shares some properties with the GRCRs, there are also differences – issues-. And, anyway, we do not understand those sources well, so this increases the mystery.”
Scientists plan to follow the object closely to look for more tracks about what could be.
“In the next decade, the Transcontinental Radiotelescope Square Kilometre Array (SKA) will come into operation. You can perform sensitive maps of heaven every day,” says Professor Murphy.
“We hope that the power of this telescope will help us solve mysteries like this last discovery, but it will also open new and vast stripes of the cosmos to exploration in the radio spectrum,” he concludes.