Mysterious radio waves emanating from the heart of the Milky Way have baffled astronomers. At this point, they have no idea what is causing them, according to a new study published Tuesday in the “Astrophysical Journal”.
A press release from the University of Sydney said the object was discovered by a team of scientists around the world, using a telescope in western Austria belonging to the agency’s Australian government scientific research.
The unusual signals coming from the direction of the center of the Milky Way – “radio waves that do not match any currently understood pattern of variable radio source” – could suggest a new class of stellar objects, according to the press release from the university.
“The strangest property of this new signal is that it has a very strong polarization. This means that its light oscillates in only one direction, but that direction rotates over time, ”said Ziteng Wang, lead author of the new study and a doctoral student at the School of Physics at the University of Sydney.
“The brightness of the object also varies considerably, by a factor of 100, and the signal turns on and off seemingly randomly. We’ve never seen anything like it, ”Wang said.
Wang explained that scientists initially thought it could be a pulsar – “a very dense type of spinning dead star – or a type of star that emits huge solar flares. “. However, the signals from the new source do not match those expected from these types of celestial objects, according to Wang.
The uniqueness of the radio signal – nicknamed ASKAP J173608.2-321635 after its contact details – was that it “started out invisibly, then turned bright and faded before reappearing again”, which is “extraordinary behavior,” said Tara Murphy, of Wang. Thesis director and professor at the Sydney Institute for Astronomy and the School of Physics.
Over a nine-month period in 2020, astronomers detected six radio signals from the source, trying to find the object in visual light, but without success, according to the press release.
Scientists turned to Parkes’ radio telescope and again failed to detect the source. However, when using the more sensitive MeerKAT radio telescope in South Africa, Murphy said that because the signal was intermittent, scientists could observe it for 15 minutes every few weeks.
Fortunately, the signal returned, but Murphy noted that the source’s behavior was “drastically different”, disappearing in a single day, whereas “it had lasted for weeks” when observed by the Australian Telescope.
This new discovery hasn’t revealed much more about the secrets of this transient radio source, and scientists continue to search for answers, according to the press release from the University of Sydney.