Myungshin Im et al. 1997 ApJ 475 457 doi:10.1086/303583
Myungshin Im1, Richard E. Griffiths1, and Kavan U. Ratnatunga1
Show affiliationsWe have identified seven (field) elliptical galaxies acting as strong gravitational lenses and have used them to measure cosmological parameters. To find the most likely value for Ωm (=Ωmatter) and Λ, we have used the combined probabilities of these lens systems having the observed critical radii (or image deflection) for the measured or estimated values of lens redshifts, source redshifts, and lens magnitudes. Our measurement gives Λ=0.64+ 0.15−0.26 if Ωm + Λ = 1, and the Ωm = 1 model is excluded at the 97% confidence level. We also find, at the 68% (Ω = 0)-82% (Ω = 0.3) confidence level, that an open universe is less likely than a flat universe with nonzero Λ. Except for the possibility of strong perturbations due to cluster potentials and the systematic overestimate of the lens magnitudes, other possible systematic errors do not seem to influence our results strongly: correction of possible systematic errors seems to increase the significance of the result in favor of a nonzero Λ model.
cosmology: observations; cosmology: theory; galaxies: elliptical and lenticular, cD; gravitational lensing
Issue 2 (1997 February 1)
Received 1996 February 29, accepted for publication 1996 August 20
Myungshin Im et al. 1997 ApJ 475 457