The phenomena of an Einstein ring that was predicted by Einstein’s theory of General Relativity but remained a mystery has recently been discovered by researchers.
An Einstein ring is a distorted image of a very distant galaxy, which is termed “the source” that produces the bending of the light rays due to a massive galaxy, termed “the lens”, lying between it and the observer.
The strong gravitational field of the lens galaxy distorts the structure of space-time in its neighbourhood, and it attracts objects which have a mass and also bends the paths of light. When the two galaxies are exactly aligned, the image of the more distant galaxy is converted into an almost perfect circle surrounding the lens galaxy. The irregularities in the circle are due to asymmetries in the source galaxy.
The PhD student Margherita Bettinelli, of the Instituto de Astrofísica de Canarias (IAC) and the University of La Laguna (ULL), together with an international team of astrophysicists has recently discovered “The Canarias Einstein ring” and the paper was published in the international journal Monthly Notices of the Royal Astronomical Society.
Bettinelli accidentally found it when she was examining data taken through the “Dark Energy Camera” (DECam) of the 4m Blanco Telescope at the Cerro Tololo Observatory, in Chile. Soon the members of the group started observing and analyzing its physical properties with the OSIRIS spectrograph on the Gran Telescopio CANARIAS (GTC).
This “Canarias Einstein ring” is one of the most symmetrical discovered until now, perfectly aligned, with a separation on the sky of only 0.2 arcseconds, with the source galaxy 10,000 million light years away.
“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,” says Antonio Aparicio, one of the IAC astrophysicts.