GALAXY-SCALE STRONG-LENSING TESTS OF GRAVITY AND GEOMETRIC COSMOLOGY: CONSTRAINTS AND SYSTEMATIC LIMITATIONS
- M.I.T. Department of Physics and Kavli Institute for Astrophysics and Space Research, 70 Vassar Street, Cambridge, MA 02139 (United States)
- Beatrice Watson Parrent Fellow, Institute for Astronomy, University of Hawai'i, 2680 Woodlawn Dr., Honolulu, HI 96822 (United States)
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 gamma = 1.01 +- 0.05, and (2) a determination of OMEGA{sub L}AMBDA = 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 gamma and OMEGA{sub L}AMBDA unless the properties of the lensing galaxies are independently constrained with substantially greater accuracy than at present.
- OSTI ID:
- 21392443
- Journal Information:
- Astrophysical Journal, Vol. 708, Issue 1; Other Information: DOI: 10.1088/0004-637X/708/1/750; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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