New results from the gravitational lensing of galaxies

Abstract

We use a sample of 53 elliptical galaxies which are lensing background emission-line galaxies and have been observed by the SLACS collaboration using HST and SDSS to place constraints on the post-Newtonian parameter 7 and the cosmological parameter A. We find y = 1.00 ± 0.04 on kiloparsec scales, consistent with the predictions of general relativity. Assuming a flat universe, we constrain QA = 0.72 ± 0.15, in agreement with results from other independent techniques and strongly excluding h = 0. We also use these lenses as a probe of galactic dynamics, finding constraints which are consistent with those obtained via other methods.