The Sloan Digital Sky Survey Quasar Lens Search. III. Constraints on Dark Energy from the Third Data Release Quasar Lens Catalog

TL;DR

This study uses the statistics of lensed quasars from SDSS to constrain dark energy parameters, confirming its consistency with a cosmological constant independently of supernova data.

Contribution

It provides new cosmological constraints from SDSS quasar lensing data, accounting for selection effects and combining with BAO measurements.

Findings

Omega_Lambda=0.74^{+0.11}_{-0.15} for w=-1

Omega_M=0.26^{+0.07}_{-0.06} and w=-1.1 extpm0.6 with BAO data

Results agree with previous radio lensing studies and support a cosmological constant

Abstract

We present cosmological results from the statistics of lensed quasars in the Sloan Digital Sky Survey (SDSS) Quasar Lens Search. By taking proper account of the selection function, we compute the expected number of quasars lensed by early-type galaxies and their image separation distribution assuming a flat universe, which is then compared with 7 lenses found in the SDSS Data Release 3 to derive constraints on dark energy under strictly controlled criteria. For a cosmological constant model (w=-1) we obtain \Omega_\Lambda=0.74^{+0.11}_{-0.15}(stat.)^{+0.13}_{-0.06}(syst.). Allowing w to be a free parameter we find \Omega_M=0.26^{+0.07}_{-0.06}(stat.)^{+0.03}_{-0.05}(syst.) and w=-1.1\pm0.6(stat.)^{+0.3}_{-0.5}(syst.) when combined with the constraint from the measurement of baryon acoustic oscillations in the SDSS luminous red galaxy sample. Our results are in good agreement with earlier lensing constraints obtained using radio lenses, and provide additional confirmation of the presence of dark energy consistent with a cosmological constant, derived independently of type Ia supernovae.