2009/07/31 by Josiah Schwab, Adam S. Bolton, A. Bolton +2
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics #Cosmology #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gravitational lens #Photometric redshift #Physics #Redshift #Strong gravitational lensing #Velocity dispersion #Weak gravitational lensing #astro-ph.CO
paper · pdf · doi:10.1088/0004-637x/708/1/750
8 pages, 5 figures; Accepted to ApJ
arxiv created 2009/12/01 · openalex publication_date 2009/12/15 · arxiv updated 2015/05/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Galaxy-scale strong gravitational lenses with measured stellar velocity dispersions allow a test of the weak-field metric on kiloparsec scales and a geometric measurement of the cosmological distance–redshift relation, provided that the mass-dynamical structure of the lensing galaxies can be independently constrained to a sufficient degree. We combine data on 53 galaxy-scale strong lenses from the Sloan Lens ACS Survey with a well-motivated fiducial set of lens-galaxy parameters to find (1) a constraint on the post-Newtonian parameter γ = 1.01 ± 0.05, and (2) a determination of Ω Λ = 0.75 ± 0.17 under the assumption of a flat universe. These constraints assume that the underlying observations and priors are free of systematic error. We evaluate the sensitivity of these results to systematic uncertainties in (1) total mass-profile shape, (2) velocity anisotropy, (3) light-profile shape, and (4) stellar velocity dispersion. Based on these sensitivities, we conclude that while such strong-lens samples can, in principle, provide an important tool for testing general relativity and cosmology, they are unlikely to yield precision measurements of γ and Ω Λ unless the properties of the lensing galaxies are independently constrained with substantially greater accuracy than at present.