Introduction

In 1979, three British-American astronomers, Walsh, Carswell and Weymann discovered by chance in the sky the first example of a gravitational lens mirage, an illusion at the cosmic scale, which consists of two images of a bright background quasar (an active galactic nucleus), formed by a gravitational lens in the foreground. The formation of such cosmic mirages had been predicted within the general relativity developed in 1917. According to this theory, Einstein predicts that light rays emitted by a distant background source are deflected near a heavy and compact foreground massive object (the lens) located along the line of sight, like a star, a galaxy or even a cluster of galaxies. Therefore, a large concentration of mass may act as a kind of lens, called a gravitational lens.


A simple educational experience makes it possible to simulate such effects (see below). Gravitational lens simulator: A didactical experiment designed by J. Surdej (Department of Astrophysics, Geophysics and Oceanography, Liege University) for RéjouiSciences (Faculty of Sciences, ULg) To buy a lens - click

You can find more informations on the DIDACTICAL EXPERIMENT ON GRAVITATIONAL LENSING page.

Introduction to the theory of gravitational lensing

Lectures No 1 - 3 (pdf files + videos:mov, avi) given by Jean Surdej (in french): Lentilles Gravitationnelles (Français 2011)

  • Lentilles gravitationnelles, Cours No 1: Astrophysique et Techniques Spatiales: Ingés aéro/ Ingés Phys 2011-2012 (Fichier PDF + vidéos: mov, m4v) Ing_1_16_09_2011.pdf, Ing_1_11_12.m4v, Ing_1_11_12.mov (lentilles gravitationnelles, début) http://hdl.handle.net/2268/74072

  • Lentilles gravitationnelles, Cours No 2: Astrophysique et Techniques Spatiales: Ingés aéro/ Ingés Phys 2011-2012 (Fichier PDF + vidéos: mov, avi, m4v) Ing_2_23_9_2011.pdf, Ing_2_10_11.mov, Ing_2_10_11.avi, Ing_2_10_11.m4v (simulateur --> point-mass lens model) http://hdl.handle.net/2268/74073

  • Lentilles gravitationnelles, Cours No 3: Astrophysique et Techniques Spatiales: Ingés aéro/Ingés Phys 2011-2012 (Fichiers pdf + vidéos: mov, avi, m4v) Ing_3_30_9_2011.pdf, Ing_3_10_11.mov, Ing_3_10_11.avi, Ing_3_10_11.m4v (SIS lens model --> fin) http://hdl.handle.net/2268/74098

Gravitational Lensing (English, short version, 2016)

  • Cours No 3: Astrophysique et Techniques Spatiales: Ingés aéro/ Ingés Phys 2015-2016 (Fichier PDF + vidéo (in english): mov), Ing_3_2_10_2015.pdf, Ing_3_2_10_2015.mov (gravitational lensing, english) http://hdl.handle.net/2268/187671