The Big Ring appears as an almost perfect ring on the sky, but Alexia’s further analysis reveals that it has more of a coil shape, like a cork-screw, that is aligned face-on with Earth. The Giant Arc, which is approximately 1/15th the radius of the observable universe, shows as an enormous, nearly symmetrical, crescent of galaxies in the remote universe. It is twice the size of the striking Sloan Great Wall of galaxies and clusters that is seen in the relatively nearby universe.

“The Big Ring and Giant Arc are the same distance from us, near the constellation of Boötes the Herdsman, meaning they existed at the same cosmic time when the universe was only half of its present age” commented Alexia. “They are also in the same region of sky, at only 12 degrees apart when observing the night sky.

“Identifying two extraordinary ultra-large structures in such close configuration raises the possibility that together they form an even more extraordinary cosmological system.

“This data we’re looking at is so far away that it has taken half the universe’s life to get to us, so from a time when the universe was about 1.8 times smaller than it is now. The Big Ring and the Giant Arc, both individually and together, gives us a big cosmological mystery as we work to understand the universe and its development.”

Alexia, together with adviser Dr Roger Clowes, both from UCLan’s Jeremiah Horrocks Institute, and collaborator Gerard Williger from the University of Louisville, USA, discovered the new structure by looking at absorption lines in the spectra of quasars from the Sloan Digital Sky Survey (SDSS).

Using the same method that led to the discovery of the Giant Arc, they observed the intervening Magnesium-II (or MgII – it means the atom has lost an electron) absorption systems back-lit by quasars, which are remote super-luminous galaxies. These very-distant, very-bright, quasars act like giant lamps shining a spotlight through distant, but much fainter, intervening galaxies that otherwise would go unseen.

Alexia has presented her findings on the Big Ring at the 243^rd meeting of the American Astronomical Society (AAS) on the 10January. The AAS invites researchers with potentially ground-breaking findings to share their work with the global astronomy community.

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