Cosmological Parameters from the SDSS DR5 Velocity Dispersion Function of Early-Type Galaxies through Radio-selected Lens Statistics
Abstract
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 semianalytical 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 to be Ωm,0=0.25+0.12-0.08 (68% CL) assuming evolutions of galaxies predicted by a semianalytical 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 nonevolving dark energy equation of state wx<-1.2 (wx<-0.5) at the 68% CL (95% CL).
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 2007
- DOI:
- 10.1086/516569
- arXiv:
- arXiv:astro-ph/0611898
- Bibcode:
- 2007ApJ...658L..71C
- Keywords:
-
- Cosmology: Cosmological Parameters;
- Galaxies: Evolution;
- Galaxies: Statistics;
- Cosmology: Gravitational Lensing;
- Astrophysics
- E-Print:
- ApJL, accepted (results and presentations revised