Astroboffins spot high-power 8b year old radio burst from pre-Earth event
Signal could help astronomers suss out the mass of the universe
An international team of scientists have discovered a fast radio burst (FRB) so distant that it blows the previous record away, but is still one of the brightest they've ever seen.
It took the signal from FRB 20220610A around eight billion years to reach Earth in June of last year, making it around 50 percent older than the previous distance record holder. In just a few milliseconds, the FRB released the same amount of energy as our Sun does in 30 years, they estimate. For reference, the average FRB is believed to release the equivalent of three days of the Sun's energy output.
Its amazing brightness means FRB 20220610A is brighter than all but one of the 55 FRBs previously detected by the Commonwealth Scientific and Industrial Research Organisation's Australian Square Kilometre Array Pathfinder (ASKAP), which discovered this one as well.
After follow-up observations of the area using the European Southern Observatory's Very Large Telescope, the Australian-led team determined that it likely came from a pair or trio of galaxies merging, which is consistent with some theories of the cause of FRBs.
Supernovae and magnetar neutron stars have been posited as other FRB causes, but no one explanation is considered to be universally applicable to cause these strange phenomena.
Unknown causes don't mean FRBs are just mysterious anomalies
Indeterminate origin aside, FRBs - especially ones as bright and distant as 20220610A - give astronomers an opportunity to try to estimate the mass of the universe, a concept first proposed by late Australian astronomer Jean-Pierre Macquart in 2020.
"If we count up the amount of normal matter in the Universe – the atoms that we are all made of – we find that more than half of what should be there today is missing," said project co-lead Professor Ryan Shannon of Swinburne University of Technology. Some of that missing mass is attributable to so-called "dark matter," but not all of it.
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"We think that the missing matter is hiding in the space between galaxies, but it may just be so hot and diffuse that it's impossible to see using normal techniques," Shannon said. "Fast radio bursts sense this ionised material. Even in space that is nearly perfectly empty they can 'see' all the electrons, and that allows us to measure how much stuff is between the galaxies."
Macquarie University's Stuart Ryder, lead author on the 20220610A research paper, said that some FRBs defy "Macquart's relation," as the late professor's theory is known, but not 20220610A.
"[Maquart] showed that the further away a fast radio burst is, the more diffuse gas it reveals between the galaxies," Ryder said. "Our measurements confirm the Macquart relation holds out to beyond half the known Universe."
The team's findings push the limit of what we know about FRBs, but they note that it'll be near impossible to spot anything further away until better equipment is built. Future observations and new FRB records will need to wait for the completion of the Square Kilometer Array Observatory, currently planned to come online in 2028. ®