Missing matter mostly missing in lensing galaxy


Figure 1: An irregular ring of radiation can be seen around the distant galaxy in the center of this 2.2-micron CCD photograph, made with the 10-meter Keck telescope on Hawaii. Just below the lensing galaxy a neighboring galaxy can be seen, which also contributes to the lensing effects. Sometimes these are called an Einstein ring. Credit: ESA and the W. M. Keck Observatory

Gravitational lensing is a prediction of Einstein’s general theory of relativity. It describes the situation where a foreground galaxy (or cluster of galaxies) acts like a light lens and focuses the light of a more distant background galaxy and hence magnifies it like a normal lens would do.  According to the theory the lens distorts the galaxy image often looking like a cross or a ring around the closer “lensing” galaxy.

Several earth-based radio and optical telescopes and the Herschel Space Observatory were used to image an object. Shown here, in Fig. 1, is where a gravitational lens is claimed to image a very distant galaxy that is apparently still in early formation. Continue reading