NOAO >   Observing Info >   Approved Programs >   2007B-0450

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Proposal Information for 2007B-0450


PI: J. Anthony Tyson, University of California, Davis, tyson@physics.ucdavis.edu
Address: Physics Department, One Shields Avenue, Davis, CA 95616, USA

CoI: Ian Dell'Antonio, Brown University
CoI: David Wittman, University of California, Davis
CoI: Vera Margoniner, University of California, Davis
CoI: David Rusin, University of California, Davis

Title: Completing the plan of the DLS: A uniform dataset for 3-D shear measurements.

Abstract: We request 1.5 nights of KPNO 4-m time to bring the level of imaging depth in DLS field F1 on a level with that achieved in the other four fields of the DLS. The data would allow us to reach our critical minimum number of fields to control for cosmic variance in the shear correlation analysis. The F1 data is currently lacking in two ways: first, about 45% of the area is imaged to only 3/4 (13,500s) depth in R. Second, about 5% of the images in the B,V,z filters have very poor (worse than 1.8\arcsec) seeing. The combination of these two effects makes the F1 dataset noticeably shallower and less uniform than that in DLS fields F2-F5. Although interesting science results are already possible with the data in hand, the resulting lack of uniformity affects both our weak lensing analyses and, equally importantly, the calibration of photometric redshifts in these fields. Because the previous DLS data on F1 has already been released, these additional images will also be available immediately; a new version of the stacked F1 data will be made public within 4 months of the data collection.


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