UCL Astrophysics Group



CLASH (Cluster Lensing And Supernova survey with Hubble) is a Hubble Space Telescope Multi-Cycle Treasury Program designed to place new constraints on the fundamental components of the cosmos: dark matter, dark energy and baryons. To accomplish this, galaxy clusters will be used as cosmic lenses to reveal dark matter and magnify distant galaxies.

The galaxy clusters are chosen based on their smooth and symmetric x-ray surface brightness profiles: "simpler" lenses to model. All clusters have masses ranging from ~5 to ~30x1014 solar masses. The redshift range covered is 0.18 < z < 0.90. Multiple observations of the same area of the sky enable a high redshift supernovae search in the surrounding field. This will allow us to improve the constraints on both the time dependence of the dark energy equation of state and on the cosmological parameters.