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2003MNRAS.346..746C -
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Mon. Not. R. Astron. Soc., 346, 746-772 (2003/December-2)
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The Cosmic Lens All-Sky Survey: statistical strong lensing, cosmological parameters, and global properties of galaxy populations.
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CHAE K.-H.
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Abstract (from CDS):
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Extensive analyses of statistical strong gravitational lensing are performed based on the final Cosmic Lens All-Sky Survey (CLASS) well-defined statistical sample of flat-spectrum radio sources and current estimates of galaxy luminosity functions per morphological type. The analyses are carried out under the assumption that galactic lenses are well-approximated by singular isothermal ellipsoids and early-type galaxies evolved passively since redshift z ∼ 1. Two goals of the analyses are: (i) to constrain cosmological parameters independently of other techniques (e.g. Type Ia supernovae magnitude-redshift relation, cosmic microwave background anisotropies, galaxy matter power spectra); and (ii) to constrain the characteristic line-of-sight velocity dispersion and the mean projected mass ellipticity for the early-type galaxy population. Depending on how the late-type galaxy population is treated (i.e. whether its characteristic velocity dispersion is constrained or not), we find for a flat universe with a classical cosmological constant that the matter fraction of the present critical density Ω_{m}0.31^{+0.27}_{–0.14}(68 per cent) for the unconstrained case or 0.40^{+0.28}_{–0.16}(68 per cent) for the constrained case, with an additional systematic uncertainty of ~0.11 arising from the present uncertainty in the distribution of CLASS sources in redshift and flux density. For a flat universe with a constant equation of state for dark energy w p_{x}(pressure)/ρ_{x}(energy density) and the prior constraint w ≥-1, we find that -1 ≤w < -0.55^{+0.18}_{–0.11}(68 per cent) for the unconstrained case or -1 ≤w < -0.41^{+0.28}_{–0.16}(68 per cent) for the constrained case, where w -1 corresponds to a classical cosmological constant. The determined value of the early-type characteristic velocity dispersion [σ^{(e)}_{*}] depends on the faint-end slope of the early-type luminosity function [α^{(e)} ] and the intrinsic shape distribution of galaxies; for equal frequencies of oblates and prolates, we find that σ^{(e)}_{*}(0.3 ≲z ≲ 1) 198^{+22}_{–18}km/s (68 per cent) for a `steep'α^{(e)} -1 or σ^{(e)}_{*}(0.3 ≲z ≲ 1) 181^{+18} _{–15}km/s (68 per cent) for a `shallow'α^{(e)} -0.54. Finally, from the relative frequencies of doubly imaged sources and quadruply imaged sources, we find that a mean projected mass ellipticity of early-type galaxies {bar}ε_{{mass}} = 0.42 with a 68 per cent lower limit of 0.28 assuming equal frequencies of oblates and prolates.

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Abstract Copyright:
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2003 RAS

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Journal keyword(s):
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gravitational lensing - methods: statistical - galaxies: haloes - galaxies: kinematics and dynamics - galaxies: structure - cosmological parameters
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Simbad objects:
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17

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2021.05.06-11:22:47

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