New giant radio galaxies offer new insight of the universe

Radio galaxies get their name from the fact that they release huge beams, or ‘jets’, of radio light.

South Africa-. Two giant radio galaxies have been discovered with South Africa’s powerful MeerKAT telescope, located in the Karoo region. Radio galaxies get their name from the fact that they release huge beams, or ‘jets’, of radio light. These happen through the interaction between charged particles and strong magnetic fields related to supermassive black holes at the galaxies’ hearts.

millions of radio galaxies are known to exist, only around 800 giants have been found. This population of galaxies was previously hidden from us by radio telescopes’ limitations. But the MeerKAT has allowed new discoveries because it can detect faint, diffuse light which previous telescopes were unable to do.

The giant radio galaxies were spotted in new radio maps of the sky created by one of the most advanced surveys of distant galaxies. The team working on it has included astronomers from around the world including South Africa, the UK, Italy and Australia. Called the International Gigahertz Tiered Extragalactic Exploration (MIGHTEE) survey, it involves data collected by South Africa’s MeerKAT radio telescope.

Their discovery means that a clearer understanding of the evolutionary pathways of galaxies is beginning to emerge. This is tantalising evidence that a large population of faint, very extended giant radio galaxies may exist. This may help us understand how radio galaxies become so huge and what sort of havoc supermassive black holes can wreak on their galaxies.