Limits on the Evolution of Galaxies from the Statistics of Gravitational Lenses

Publisher Website
Google Scholar
Abstract
We use gravitational lenses from the Cosmic Lens All-Sky Survey to constrain the evolution of galaxies since redshift z ~ 1 in the current Λ cold dark matter cosmology. This constraint is unique as it is based on a mass-selected lens sample of galaxies. Our method of statistical analysis is the same as that done in recent work by K.-H. Chae. We parameterize the early-type number density evolution in the form of (1 + z) and the velocity dispersion in the form of (1 + z). We find that νn = -0.11 (1 σ) if we assume νv = 0, implying that the number density of early-type galaxies is within 50%-164% of the present-day value at redshift z = 1. Allowing the velocity dispersion to evolve, we find that νv = -0.4 (1 σ), indicating that the velocity dispersion must be within 57%-107% of the present-day value at z = 1. These results are consistent with the early formation and passive evolution of early-type galaxies. More stringent limits from lensing can be obtained from future large lens surveys and by using very high redshift quasars (z 5) such as those found from the Sloan Digital Sky Survey.
All Related Versions