Cosmography with lensed quasars (Cecile Faure, Laboratoire d'Astrophysique de l'Ecole Polytechnique Fédérale de Lausanne, Switzerland)

Strong gravitational lensing offers a unique opportunity to map the mass distribution in galaxies and to measure the Hubble constant, Ho, at cosmological distance and independent of any standard candle. The COSMOGRAIL collaboration is monitoring about 30 lensed quasars since 2004 with the goal of measuring the so-called "time delays" between the lensed images, a quantity directly related to Ho and to the slope of the mass distribution in lensing galaxies. I will show recent results of our monitoring campaign and improved tools to measure the time-delays and model the lenses.