EPFL Scientists at EPFL focus on the phenomenon of strong gravitational lensing. This occurs when a massive galaxy (a.k.a. the lens), a group of galaxies or a cluster of galaxies deviate light rays from another source of light in the background. This background source is then seen multiple times and often brighter than it actually is. Strong lenses offer many scientific applications. They can be used as a natural (gravitational) telescope that naturally magnifies distant objects. They can be used to weigh lens galaxies, including their Dark Matter content, or to measure the expansion rate of the Universe known as the Hubble constant. However, strong lenses are rare: among the billions of galaxies Euclid will see, only 100’000 such objects are expected. EPFL is in charge of finding them with artificial intelligence techniques.

Contact person: frederic.courbin@epfl.ch