Cosmic burst baffles radio astronomers

ASTRONOMERS have detected a cosmic ‘pulse’ that has travelled through space for eight billion years or more than half the age of the universe since the Big Bang to reach detectors on Earth.
The source of the burst of radio waves named FRB 20220610A is a group of two or three galaxies merging at a time when the first stars, planets and galaxies appeared including Alpha Centauri, the closest star to our solar system formed 4.6 billion years ago. The universe is 13.8 billion years old.
The Australian-led international team used the CSIRO Australian Square Kilometre Array Pathfinder radio telescope in the Murchison 800km north of Perth to determine its precise location and said the burst was so intense it unleashed in less than a millisecond the same amount of energy our sun emits in 30 years.
“That is enough power to microwave a bowl of popcorn about two times the size of the sun,” according to Ryan Shannon, Swinburne University of Technology astronomer and co-leader of the study published in the US journal Science (www.science.org).
The location of FRB 20220610A was imaged by three of the world’s biggest optical telescopes, Keck, Gemini South and the European Southern Observatory Very Large Telescope in Chile.
Fast radio bursts (FRBs) are pulses of radio-frequency electromagnetic radiation emitted by highly magnetised stars called magnetars, the stellar corpses the mass of the sun and size of a small city.
FRBs usually last just a fraction of a second, outshining most sources of radio waves in the universe. The latest burst detected in 2022 travelled the longest of any burst detected to date and outdates the oldest known such burst by three billion years.
Associate Professor Shannon says FRBs produce all their energy in radio waves, nothing in optical light or X-rays. They are invisible to the naked eye, but to a radio telescope they outshine everything else in the sky for a few thousandths of a second.
He says more than 100,000 FRBs are estimated to occur daily somewhere in the universe. Few have been detected and only about 50 (nearly half using ASKAP) traced back to the galaxy in which they originated.
The first FRB was detected in 2006. Future work is expected to detect even older and more distant bursts and allow observers to look back in time to pin down their host galaxies and ‘see’ the structure of galaxies and dark matter between them.

* The artist’s impression, not to scale, illustrates the path of a fast radio burst from the distant galaxy where it originated to Earth eight billion years away.