NOAO >   Observing Info >   Approved Programs >   2013A-0360

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Proposal Information for 2013A-0360


PI: Anja von der Linden, KIPAC / Stanford University, anja@slac.stanford.edu
Address: 452 Lomita Mall, Stanford, CA 94305

CoI: Steven Allen, KIPAC / Stanford University
CoI: Adam Mantz, KICP / U Chicago
CoI: Douglas Applegate, U Bonn
CoI: Patrick Kelly, KIPAC / Stanford University

Title: Setting the Scale: Determining the Absolute Mass Normalization and Scaling Relations for Clusters at z~0.1

Abstract: We propose to establish a low-redshift anchorpoint for the absolute mass calibration of galaxy clusters, an essential prerequisite for precise measurements of dark energy from current and future cluster surveys. To do so, we propose DECam imaging of 30 massive, X-ray- selected galaxy clusters at z~0.1 to estimate their masses via weak lensing. We propose \it ugriz imaging, as robust photo-z estimates of background galaxies are essential for controlling systematic errors in weak lensing mass measurements to a few percent. The data requested here will more than double the number of clusters in cosmological cluster samples with accurate weak lensing mass estimates employing photo-z's, enabling us for the first time to determine the mass normalization of key mass-observable relations to within 5%, and measure \sigma_8 to 2%. Together with existing X-ray observations, these data will allow us to measure the shape (deviations from a power- law?) and scatter (size, and deviations from log-normal?) of cluster scaling relations, key ingredients for relating survey observables to cluster masses. Additionally, these data will create a legacy dataset of massive, low-redshift cluster fields with robust photo-z estimates.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2013A-0360

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