DES redblackred

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SDSS 2.5 meter telescope
SDSS-I 2000-5 Apache Point Observatory
SDSS-II
2005-8 New Mexico
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Frieman etal 2008, Sako etal 2008
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SDSS Supernova Survey
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Preliminary Cosmology Results
w open
Kessler, et al. 2008
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Cluster Spatial Correlations
MaxBCG catalog 40,000 clusters with photometric
redshift estimates (Koester etal Annis) Model
impact of photo-z errors and non-linearity on 3D
clustering Estrada, Sefusatti, Frieman
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Statistical Weak Lensing by SDSS Galaxy Clusters
Mean Tangential Shear Profile in Bins of Cluster
Optical Richness (Ngal), measured to 30 h?1
Mpc Sheldon, etal 2007
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Statistical Weak Lensing by SDSS Galaxy Clusters
Halo Model of Cluster Shear Profiles robust
determination of mean virial mass vs.
richness Johnston, etal 2007
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Statistical Weak Lensing Calibrates Cluster
Mass-Richness Relation
Cluster Mass vs. Richness Future use this to
independently calibrate, e.g., SZE or richness
vs. Mass Cluster cosmology with DES
SDSS Data zlt0.3
Statistical Lensing eliminates projection
effects of individual cluster mass estimates
Johnston, etal 2007
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Photometric Redshifts
Elliptical galaxy spectrum
Measure relative flux in multiple
filters track the 4000 A break Estimate
individual galaxy redshifts with accuracy
?(z) lt 0.1 (0.02 for clusters) Precision is
sufficient for Dark Energy probes,
provided error distributions well
measured. Good detector response in z
band filter needed to reach zgt1

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Galaxy Photo-z Simulations
VHS
DES griz
DES
DES griZY VHS JHKs on ESO VISTA 4-m enhances
science reach
10? Limiting Magnitudes g 24.6 r 24.1
i 24.0 z 23.9 2 photometric
calibration error added in quadrature Key
Photo-z systematic errors under control using
existing spectroscopic training sets to DES
photometric depth low-risk
J 20.3 H 19.4 Ks 18.3
Z 23.8 Y 21.6
Vista Hemisphere Survey
Developed improved Photo-z Error Estimates and
robust methods of outlier rejection Cunha, Lima,
Oyaizu (UC students), Frieman, Lin
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Bias
Variance and Bias of Photo-z Estimates
Variance
Cunha etal