An international team of astronomers have captured the image of something never seen before, a “ring of cosmic fire” as it existed 11 billion years ago. It is a distant galaxy, called R5519, which has approximately the mass of ours, the Milky Way, and is circular with a hole in the middle, rather like a “titanic donut.” Craft stars at devilish speed. “It is super rare,” admit its discoverers. The finding, announced in the journal “Nature Astronomy,” may shake theories about the earliest formation of galactic structures.
“It is a very curious object that we have never seen before,” says lead researcher Tiantian Yuan of Australia’s ARC Center of Excellence for All-Sky Astrophysics in 3 Dimensions (ASTRO 3D). “It seems strange and familiar at the same time.”
Located 11 billion light-years from the Solar System, R5519 was discovered in data from the WM Keck Observatory in Hawaii and NASA’s Hubble Space Telescope. The black hole at its center is truly massive, with a diameter 2 billion times as long as the distance from Earth to the Sun. Monstrous. To put it another way, it is three million times larger than the diameter of the supermassive black hole in the Messier 87 galaxy, which in 2019 became the first to be directly photographed.
“It is making stars 50 times faster than the Milky Way,” says Yuan, a member of ASTRO 3D based at the Swinburne University of Technology Center for Astrophysics and Supercomputing, in the state of Victoria. “Most of that activity takes place in your ring, so it really is a ring of fire.”
There are two types of ring galaxies. The most common is created by internal processes. But the second is formed by collision, as a result of immense and violent encounters with other galaxies. From what researchers have seen, R5519 is one of those collision ring galaxies, “making it the first to be found in the early Universe.
In the nearby “local” Universe, these collision ring galaxies are 1,000 times rarer than the internally created type. Images of the R5519, just 3 billion years after the Big Bang, indicate that they have always been extremely rare.
Ahmed Elagali of the International Radio Astronomy Research Center in Western Australia believes that studying R5519 would help determine when spiral galaxies began to develop. “Furthermore, restricting the number density of ring galaxies through cosmic time can also be used to impose restrictions on the assembly and evolution of groups of local galaxies,” he adds.
Along the same lines, Kenneth Freeman, professor at the National University of Australia and co-author of the study, assures that the discovery will have implications for understanding how galaxies such as the Milky Way formed. “Ring galaxy collision formation requires a thin disk to be present in the ‘victim’ galaxy before the collision occurs,” he explains.
“The thin disk is the defining component of spiral galaxies: Before assembling, galaxies were in a disordered state, not yet recognizable as spiral galaxies,” he adds. As he explains, “In the case of this ring galaxy, we are looking back at the early universe 11 billion years ago, at a time when thin discs were just assembling. In comparison, the thin disk of our Milky Way began to come together just 1 billion years ago. This discovery is an indication that disk assembly in spiral galaxies occurred over a longer period than previously thought. ” .