Understand
Future large ensembles of time delay lenses have the potential to provide interesting cosmological constraints complementary to those of other methods.
- In a flat universe with constant w including a Planck prior, LSST time delay measurements for ~4,000 lenses should constrain the local Hubble constant h to ~0.007 (~1%), Omega_DE to ~0.005, and w to ~0.026 (all 1-sigma precisions).
- Similar constraints could be obtained by a dedicated gravitational lens observatory (OMEGA) which would obtain precise time delay and mass model measurements for ~100 well-studied lenses.
- We compare these constraints (as well as those for a general cosmology) to the "optimistic Stage IV" constraints expected from weak lensing, supernovae, baryon acoustic oscillations, and cluster counts, as calculated by the Dark Energy Task Force.