8bn-year-old radio burst could help weigh the universe

20 Oct 2023

Image: ESO/M Kornmesser

The researchers claim this is the most distant fast radio burst ever detected, originating from a group of merging galaxies.

A team of astronomers claim to have detected the most distant fast radio burst to date, which could be used to measure the matter between galaxies.

The researchers first discovered the energy burst in June 2022 with the Australia Square Kilometre Array Pathfinder (ASKAP) telescope. It is believed that the energy was created from a powerful cosmic event that released the equivalent of 30 years of our sun’s total emission in milliseconds.

By using an array of dishes connected to the radio telescope, the team was able to determine where the radio burst came from. They then used the European Southern Observatory’s Very Large Telescope to search for the source galaxy.

The astronomers claim that this burst of energy is older and further away than any other fast radio burst detected to date. It is believed to have originated from a small group of merging galaxies.

A yellow line between one galaxy and a small group of merging galaxies, with space in the background.

Artistic representation of the fast radio burst travelling from distant merging galaxies. Image: ESO/M. Kornmesser

The researchers said roughly 50 fast radio bursts have been pinpointed to date, but believe that we should be able to detect thousands of them. These radio bursts could also be used to properly measure the mass of the universe, according to the study.

The team said that current methods for estimating the mass of the universe give conflicting answers and challenge the standard model of cosmology. But the latest discovery suggests that these radio bursts can be used to measure the “missing” matter between galaxies to accurately weigh up the universe.

“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 Prof Ryan Shannon who co-led the study. “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.”

The team said that in 2020, the late Australian astronomer Jean-Pierre Macquart showed that fast radio bursts reveal more diffuse gases between galaxies if they are further away. The team claims their latest discovery helps to confirm this Macquart relation.

“While we still don’t know what causes these massive bursts of energy, the paper confirms that fast radio bursts are common events in the cosmos and that we will be able to use them to detect matter between galaxies, and better understand the structure of the universe.”

However, the team believes that the latest result represents the limit of what we can spot with modern telescopes and that more powerful devices will be needed to measure more distant fast radio bursts.

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Leigh Mc Gowran is a journalist with Silicon Republic