Euclid finds complete Einstein Ring in NGC galaxy

Gravitational lenses are rare in the sky – galaxies bending the light-paths of light from other galaxies behind them to form distorted or even multiple images. Even rarer is a perfect alignment of the two galaxies with us, the obervers, with the light being bent into a so-called Einstein Ring. And the rarest case was now observed by Euclid: this happening in an extremely nearby NGC galaxy. Gravitational lensing is the effect of mass bending space and light following along this bent space. If the masses are high enough, as for a galaxy, then this can lead to an image of an object behind a galaxy to be distorted or even split up into several images: a strong gravitational lens. If vary rare cases – for a perfect alignment of source, galaxy, and observer on a line – the image gets bent into a ring. These so-called Einstein Rings have been found before, but in all configurations only approximately 1000 gravitational galaxy–galaxy lenses are currently known across the sky. Principle behin ... Read full article.