Astronomers 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.
The galaxy, which has roughly the mass of the Milky Way, is circular with a hole in the middle, like a titanic doughnut; its discovery is set to shake up theories about the earliest formation of galactic structures and how they evolve.
The study, which includes data from W. M. Keck Observatory on Maunakea, was published in a recent issue of the journal Nature Astronomy.
“It is a very curious object that we’ve never seen before,” said lead researcher Tiantian Yuan, from Australia’s ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D). “It looks strange and familiar at the same time.”
The galaxy, named R5519, is 11 billion lightyears from the Solar System. The hole at its center is truly massive, with a diameter two billion times longer than the distance between the Earth and the Sun. To put it another way, it is three million times bigger than the diameter of Powehi, the supermassive black hole in the galaxy Messier 87, which in 2019 became the first ever to be directly imaged.
“It is making stars at a rate 50 times greater than the Milky Way,” said Yuan, who is an ASTRO 3D Fellow based at the Centre for Astrophysics and Supercomputing at Swinburne University of Technology, in the state of Victoria. “Most of that activity is taking place on its ring — so it truly is a ring of fire.”
To identify the unusual structure, Yuan worked with colleagues from around the U.S., Australia, Canada, Belgium and Denmark, using Keck Observatory’s adaptive optics combined with its OH-Suppressing Infrared Imaging Spectrograph (OSIRIS), as well as the Observatory’s Multi-Object Spectrograph for Infrared Exploration (MOSFIRE) to gather spectroscopic data of the ring galaxy. The team also used images recorded by NASA’s Hubble Space Telescope.