Center for Cosmology and Astro-Particle Physics
Great Lakes Cosmology Workshop VIII, June, 1-3, 2007
Probing Dark Energy with Cluster-Galaxy Weak Lensing
JAIYUL YOO AND DAVID WEINBERG
DEPARTMENT OF ASTRONOMY, THE OHIO STATE UNIVERSITY
• cluster-matter cross correlation (profile & bias)
• stacking rank-ordered clusters: monotonic relation of the mean mass-observable no mass estimate of individual clusters no accurate relation to true cluster mass
• weak lensing of the stacked sample of clusters
Cluster-Galaxy Weak Lensing
PROBING DARK ENERGY WITH CLUSTER-GALAXY WEAK LENSING
Why Robust?
• stacked sample
PROBING DARK ENERGY WITH CLUSTER-GALAXY WEAK LENSING
Why Robust?
• stacked sample
PROBING DARK ENERGY WITH CLUSTER-GALAXY WEAK LENSING
Why Robust?
• stacked sample ≅ mass-ordered
clusters
PROBING DARK ENERGY WITH CLUSTER-GALAXY WEAK LENSING
Why Robust?
• stacked sample ≅ mass-ordered
clusters
• works for arbitrary relation and bias
PROBING DARK ENERGY WITH CLUSTER-GALAXY WEAK LENSING
Cosmological Probe?• stacked sample is
set by cosmology!
• growth factor, volume, halo mass function (given number of clusters)
• constituent clusters are also different!
PROBING DARK ENERGY WITH CLUSTER-GALAXY WEAK LENSING
Prediction and Observable
PROBING DARK ENERGY WITH CLUSTER-GALAXY WEAK LENSING
angular diameter distance
critical surface density
• clusters provide high S/N (vs cosmic shear)
• spherical symmetric dark matter halo
• apparent lens center (central cD galaxies)
• stacking increases S/N → high redshift clusters
• tangential shear profile
Why Better?
• clusters provide high S/N (vs cosmic shear)
• spherical symmetric dark matter halo
• apparent lens center (central cD galaxies)
• stacking increases S/N → high redshift clusters
• tangential shear profile
PROBING DARK ENERGY WITH CLUSTER-GALAXY WEAK LENSING
Parameter Sensitivity
PROBING DARK ENERGY WITH CLUSTER-GALAXY WEAK LENSING
28.0m24.0m20.0m
Parameter Sensitivity
PROBING DARK ENERGY WITH CLUSTER-GALAXY WEAK LENSING
Dark Energy Constraint
PROBING DARK ENERGY WITH CLUSTER-GALAXY WEAK LENSING
• DES type survey
• 1,2,3 σ contours
• no CMB priors
• flat universe
Conclusion and Prospects
• novel method of cluster-galaxy weak lensing works for arbitrary mass-observables robust to scatter and bias
• readily applicable, strong constraints
• application to OSU Dark Energy Survey with Large Binocular Telescope (LBT)
PROBING DARK ENERGY WITH CLUSTER-GALAXY WEAK LENSING
Stay “fine” tuned!!!