Cluster Lensing And Supernova survey with Hubble (CLASH): An Overview
Creators: name: Postman, Marc
name: Coe, Dan
name: Benitez, Narciso
name: Bradley, Larry
name: Broadhurst, Tom
name: Donahue, Megan
name: Ford, Holland
name: Graur, Or
name: Graves, Genevieve
name: Jouvel, Stephanie
name: Koekemoer, Anton
name: Lemze, Doron
name: Medezinski, Elinor
name: Molino, Alberto
name: Moustakas, Leonidas
name: Ogaz, Sara
name: Riess, Adam
name: Rodney, Steve
name: Rosati, Piero
name: Umetsu, Keiichi
name: Zheng, Wei
name: Zitrin, Adi
name: Bartelmann, Matthias
name: Bouwens, Rychard
name: Czakon, Nicole
name: Host, Ole
name: Infante, Leopoldo
name: Jha, Saurabh
name: Jimenez-Teja, Yolanda
name: Kelson, Daniel
name: Lahav, Ofer
name: Lazkoz, Ruth
name: Maoz, Dani
name: McCully, Curtis
name: Melchior, Peter
name: Meneghetti, Massimo
name: Merten, Julian
name: Moustakas, John
name: Nonino, Mario
name: Patel, Brandon
name: Regos, Eniko
name: Seitz, Stella
name: Sayers, Jack
name: Golwala, Sunil
name: Van der Wel, Arjen
Publisher: name: arXiv
Year: 2011
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The Cluster Lensing And Supernova survey with Hubble (CLASH) is a 524-orbit multi-cycle treasury program to use the gravitational lensing properties of 25 galaxy clusters to accurately constrain their mass distributions. The survey, described in detail in this paper, will definitively establish the degree of concentration of dark matter in the cluster cores, a key prediction of CDM. The CLASH cluster sample is larger and less biased than current samples of space-based imaging studies of clusters to similar depth, as we have minimized lensing-based selection that favors systems with overly dense cores. Specifically, twenty CLASH clusters are solely X-ray selected. The X-ray selected clusters are massive (kT &gt; 5 keV; 5 - 30 x 10^14 M_solar) and, in most cases, dynamically relaxed. Five additional clusters are included for their lensing strength (Einstein radii &gt; 35 arcsec at z_source = 2) to further quantify the lensing bias on concentration, to yield high resolution dark matter maps, and to optimize the likelihood of finding highly magnified high-redshift (z &gt; 7) galaxies. The high magnification, in some cases, provides angular resolutions unobtainable with any current UVOIR facility and can yield z &gt; 7 candidates bright enough for spectroscopic follow-up. A total of 16 broadband filters, spanning the near-UV to near-IR, are employed for each 20-orbit campaign on each cluster. These data are used to measure precise (sigma_phz &lt; 0.02(1+z)) photometric redshifts for dozens of newly discovered multiply-lensed images per cluster. Observations of each cluster are spread over 8 epochs to enable a search, primarily in the parallel fields, for Type Ia supernovae at z &gt; 1 to improve constraints on the time dependence of the dark energy equation of state and the evolution of such supernovae in an epoch when the universe is matter dominated.
description: Accepted for publication in the Astrophysical Journal Supplements, 22 pages, 16 figures. Updated Tables 3,4,8 and figures 6 and 8 to reflect replacement of Abell 963 with Abell 1423 in CLASH survey. A963 cannot be observed with WFC3 due to the lack of usable guide stars