jason rhodes, jpl 207 th aas meeting, january 10, 2006 nick scoville, cosmos pi cosmos lensing team:...
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Jason Rhodes, JPL207th AAS Meeting, January 10, 2006
Nick Scoville, COSMOS PI
COSMOS Lensing Team:Jean-Paul Kneib, Jason Rhodes, Justin Albert, David Bacon, Joel Berge, Richard Ellis, Cécile Faure, Catherine Heymans, Anton Koekemoer, Alexie Leauthaud, Richard Massey, Yannick Mellier, Satoshi Miyazaki, John Peacock, Alexandre Refregier, Elisabetta Semboloni, Lidia Tasca, James Taylor, Ludovic Van Waerbeke
Mapping the Dark Matter with COSMOS
If there is any intervening large-scale structure, light follows the distorted path (exaggerated). Background images are magnified and sheared by ~2%, mapping a circle into an ellipse. Lensing is most effective for mass structures half way between the source and the observer.
zobserver=0
zgalaxy≈1
zlens≈0.3–0.5
Weak lensing effect cannot be measured from any individual galaxy.
Must be measured statistically over many galaxies
Weak Gravitational Lensing
COSMOS For WL
•2 square degrees•Single orbit F814(I) ACS images•~80 resolved galaxies per square arcmin•versus ~30 from the ground•Unique combination of area, depth and resolution
•Opens door for unprecedented dark matter maps
The PSF Problems
•PSF time variability•output image size•CTE degradation
See Rhodes et al 2006, astro-ph/0512170
The Dark Matter Distribtuion
Created with method of Kaiser and Squires (1993)
Wavelet reconstruction will do better
E/B Decompsosition
Conclusions- the detections are real and B modes are decreasing as we improve our PSF models