Doctoral student Margherita Bettinelli from the Instituto de Astrofisica de Canarias (IAC) and the University of La Laguna (ULL) along with the team discovered this rare phenomenon while analysing images of the Sculptor dwarf galaxy.
The phenomena, predicted by Albert Einstein's theory of General Relativity, is quite rare but scientifically interesting. The interest is sufficiently strong that this object has been given its own name: "The Canarias Einstein ring".
The chance discovery was made when Bettinelli was examining data taken through the "Dark Energy Camera" (DECam) of the 4m Blanco Telescope at the Cerro Tololo Observatory in Chile.
She noticed the peculiar morphology of the Einstein ring.
The "Canarias Einstein ring" is one of the most symmetrical discovered until now and is almost circular, showing that the two galaxies are almost perfectly aligned.
The source galaxy is 10 trillion light years away from us.
Due to the expansion of the Universe, this distance was smaller when its light started on its journey to us, and has taken 8,500 million years to reach us.
"We observe it as it was then: a blue galaxy which is beginning to evolve, populated by young stars which are forming at a high rate. The lens galaxy is nearer to us, 6,000 million light years away, and is more evolved. Its stars have almost stopped forming, and its population is old," the authors noted.
"Studying these phenomena gives us especially relevant information about the composition of the source galaxy, and also about the structure of the gravitational field and of the dark matter in the lens galaxy," explained Antonio Aparicio, one of the astrophysicts who is leading the research.
The results were published in the international journal Monthly Notices of the Royal Astronomical Society.