Einstein cross


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Einstein cross

(ÿn -stÿn) A gravitationally-lensed image of a distant quasar (redshift 1.7) by a foreground (redshift 0.039) spiral galaxy. The image of the quasar is split into four point sources forming a cross at the center of the galaxy. Gravitational microlensing has been observed as variations in the light between the four components. See gravitational lens.
References in periodicals archive ?
The result is a classic Einstein Cross (shown), the first ever for a Type la supernova.
Named the Refsdal supernova in honour of Norwegian scientist Sjur Refsdal, the first scientist to propose the use of time-delayed images from galaxies undergoing gravitational lensing to study the universe's expansion, the explosion occurred 10 billion years ago, and was first observed by Hubble in November 2014, in four separate images taken around the Einstein Cross, a rare, distant galactic arrangement in outer space.
The light source in the Einstein Cross is a quasar approximately ten billion light-years away, whereas the foreground lensing galaxy is ten times closer.
The combination of this natural magnification with the use of a big telescope provides us with the sharpest details ever obtained," explained Frederic Courbin, leader of the programme studying the Einstein Cross with ESO's Very Large Telescope.
The best example of this is the original Einstein Cross, a lensed quasar numbered 2237+0305.