Rare ring galaxy captured 11 billion light-years away

Astronomers from the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) have captured an image of a super-rare type of galaxy, described as a 'cosmic ring of fire', as it existed 11 billion years ago, just a few billion years after the big bang.

The galaxy, which has roughly the mass of the Milky Way, is circular with a hole in the middle, rather like a very, very big doughnut. Its discovery is set to shake up theories about the earliest formation of galactic structures and how they evolve.

‘It is a very curious object that we’ve never seen before,’ says lead researcher, Dr Tiantian Yuan, from ASTRO 3D and based at the Centre for Astrophysics and Supercomputing at Swinburne University of Technology. ‘It looks strange and familiar at the same time.’

The galaxy, named R5519, is 11 billion light-years from the Solar System. The massive hole at its centre has a diameter two billion times longer than the distance between the Earth and the Sun, and three million times bigger than the supermassive black hole in the galaxy Messier 87, which was the first ever to be directly imaged in 2019.

The evidence suggests it is a type known as a ‘collisional ring galaxy’, formed by immense and violent encounters with other galaxies. Extremely rare in the local universe, R5519 is the first of its kind ever to be located in the early Universe.

Working with colleagues from around Australia, US, Canada, Belgium and Denmark, Dr Yuan used spectroscopic data gathered by the WM Keck Observatory in Hawaii and images recorded by NASA’s Hubble Space Telescope to identify the unusual structure.

The ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions is administered by The Australian National University.

Dr Yuan says that the unusual galaxy is making stars at a rate 50 times greater than the milky way. ‘Most of that activity is taking place on its ring – so it truly is a ring of fire.’