Extinction curves of lensing galaxies out to z=1

We present a survey of the extinction properties of 10 lensing galaxies, in the redshift range z = 0.04-1.01, using multiply lensed quasars imaged with the ESO VLT in the optical and near-infrared. The multiple images act as standard light sources'' shining through different parts of the lensing galaxy, allowing for extinction studies by comparison of pairs of images. We explore the effects of systematics in the extinction curve analysis, including extinction along both lines of sight and microlensing, using theoretical analysis and simulations. In the sample, we see variation in both the amount and type of extinction. Of the 10 systems, seven are consistent with extinction along at least one line of sight. The mean differential extinction for the most extinguished image pair for each lens is (A) over bar (V) = 0.56 +/- 0.04, using Galactic extinction law parameterization. The corresponding mean (R) over bar (V) 2.8 +/- 0.4 is consistent with that of the Milky Way at RV 3.1, where Rv = A(V)/E(B-V). We do not see any strong evidence for evolution of extinction properties with redshift. Of the 10 systems, B1152+199 shows the strongest extinction signal of A(V) 2.43 +/- 0.09 and is consistent with a Galactic extinction law with Rv = 2.1 +/- 0.1. Given the similar redshift distribution of SN Ia hosts and lensing galaxies, a large space-based study of multiply imaged quasars would be a useful complement to future dark energy SN Ia surveys, providing independent constraints on the statistical extinction properties of galaxies up to z similar to 1.