Gravitational lenses as cosmic rulers: Ωm, ΩΛ from time delaysand velocity dispersions

摘要

We show that a cosmic standard ruler can be constructed from the joint measurement of the time delay, Δτ, between gravitationallylensed quasar images and the velocity dispersion, σ, of the lensing galaxy. This is specifically shown, for a singular isothermal spherelens, DOL ∝ Δτ/σ2, where DOL is the angular diameter distance to the lens. Using MCMC simulations we illustrate the constraints setin the Ωm - ΩΛ plane from future observations.