The Parks Telescope in Australia. (Photo by Amanda Slater via Wikimedia Commons)
By Mark Waghorn via SWNS
Mysterious radio signals have reached Earth…from a galaxy far, far away.
The strange beams are known as fast radio bursts (FRBs) – and last only a millisecond.
Each pulse carries as much energy as our Sun emits in a century, say scientists.
They are coming from the edge of a dwarf galaxy three billion light-years from Earth.
It has been suggested the flashes are messages from alien civilizations with technology far advanced from our own.
Another theory suggests that bursts come about when incredibly dense matter, as in a black hole or neutron star, collides and subsequently explodes.
A second theory is that FRBs result when distant stars collapse. Their unknown origin poses challenges for astronomy as well as physics.
The fast radio burst, named FRB 20190520B, is now providing clues that may help solve the puzzle.
Illustration via SWNS
It is the first to produce signals, detectable by at least one and sometimes multiple telescopes, every time it was viewed.
Such reliability makes it an ideal target for follow-up studies.
An international team carried out a monitoring campaign using the Parkes Telescope in Australia and the Green Bank Telescope (GBT) in the United States.
The combined analyses were based on observational efforts across three continents.
Lead author Dr. Dai Shi, of Western Sydney University, said: “A total of 113 bursts from FRB 20190520B were detected by the Parkes telescope, exceeding the sum of the number of fast radio bursts previously discovered at Parkes.”
Through a combined analysis of data from GBT and Parkes, the researchers also discovered magnetic fields twisted around them.
Dr. Feng Yi, of Zhejiang Laboratory, China and Anna Thomas, from West Virginia University (WVU) measured its polarisation properties and found that the Faraday rotation measure (RM) twice changed its sign in dramatic fashion.
The Parkes Telescope in Australia (CSIRO via Wikimedia Commons)
During the propagation of a burst signal, the polarisation characteristics can be affected by the surrounding plasma.
Corresponding author Dr. Li Di, of the Chinese Academy of Sciences, Beijing, said: “The RM can be approximated by the integral product of magnetic field and electron density. Variation in RM can be caused by either factor, but a sign change has to arise from the reversal of magnetic fields, as the electron density cannot go negative.”
The reversal could result from propagation through a turbulent, magnetized screen of plasma.
Co-author Professor Yang Yuanpei, from Yunnan University, China, said: “The turbulent components of the magnetic field around repeating fast radio bursts may be as messy as a ball of wool.”
The likely scenario for producing such a mess includes the signal passing through the halo of a companion, be it a black hole or a massive star with winds.
Understanding drastic changes in the magnetized environment around the FRB is an important step toward understanding the origin of such cosmic explosions.
The study is in the journal Science.