Special Astronomy Seminar

The total solar eclipse of 1919 unveiled the gravitational lens nature of our Sun. The next example of another gravitational lens was discovered in 1979. Originally considered as a mere curiosity, gravitational lensing has matured, during the last two decades, into a genuine astrophysical tool, used in a large variety of problems, from planet search to the quest for the most distant galaxies.

We shall present cosmological results obtained at EPFL about (i) strong lensing and time delays, related to the measurements of the Hubble constant ; (ii) micro lensing and the measurement of the size of the accretion disk of a quasar, and (iii) the first cases of quasars playing the role of gravitational lenses. We shall conclude with the recently selected ESA satellite Euclid, which will investigate dark energy and dark matter through their impact on gravitational lensing.