Cosmological Parameters from the SDSS DR5 Velocity Dispersion Function of Early-type Galaxies through Radio-Selected Lens Statistics
نویسنده
چکیده
We improve strong lensing constraints on cosmological parameters in light of the new measurement of the velocity dispersion function of early-type galaxies based on the SDSS DR5 data and recent semi-analytical modeling of galaxy formation. Using both the number statistics of the CLASS statistical sample and the image separation distribution of the CLASS and the PANELS radio-selected lenses, we find the cosmological matter density Ωm,0 = 0.25 +0.12 −0.08 (68% CL) assuming evolutions of galaxies predicted by a semi-analytical model of galaxy formation and Ωm,0 = 0.26 +0.12 −0.08 assuming no evolution of galaxies for a flat cosmology with an Einstein cosmological constant. For a flat cosmology with a generalized dark energy, we find the non-evolving dark energy equation of state wx < −1.2 (wx < −0.5) at the 68% CL (95% CL). Subject headings: cosmological parameters — galaxies: evolution — galaxies: statistics — gravitational lensing
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