Dark Energy Constraints from the CTIO Lensing Survey
Abstract
We perform a cosmological parameter analysis of the 75 deg^{2} CTIO lensing survey in conjunction with cosmic microwave background (CMB) and Type Ia supernovae data. For ΛCDM cosmologies, we find that the amplitude of the power spectrum at low redshift is given by σ_{8}=0.81^{+0.15}_{0.10} (95% confidence level), where the error bound includes both statistical and systematic errors. The total of all systematic errors is smaller than the statistical errors, but they do make up a significant fraction of the error budget. We find that weak lensing improves the constraints on dark energy as well. The (constant) dark energy equation of state parameter, w, is measured to be 0.89^{+0.16}_{0.21} (95% c.l.). Marginalizing over a constant w slightly changes the estimate of σ_{8} to 0.79^{+0.17}_{0.14} (95% c.l.). We also investigate variable w cosmologies but find that the constraints weaken considerably; nextgeneration surveys are needed to obtain meaningful constraints on the possible time evolution of dark energy.
 Publication:

The Astrophysical Journal
 Pub Date:
 June 2006
 DOI:
 10.1086/503418
 arXiv:
 arXiv:astroph/0502243
 Bibcode:
 2006ApJ...644...71J
 Keywords:

 Cosmology: Gravitational Lensing;
 Cosmology: LargeScale Structure of Universe;
 Astrophysics
 EPrint:
 10 pages, 4 figures, v3 matches version accepted by ApJ. Significant changes in section 4.2.3. Otherwise, mostly minor changes