Cluster Lensing And Supernova survey with Hubble (CLASH): An Overview
Abstract
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 > 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 > 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 > 7) galaxies. The high magnification, in some cases, provides angular resolutions unobtainable with any current UVOIR facility and can yield z > 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 < 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 > 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.
Cite
@article{arxiv.1106.3328,
title = {Cluster Lensing And Supernova survey with Hubble (CLASH): An Overview},
author = {Marc Postman and Dan Coe and Narciso Benitez and Larry Bradley and Tom Broadhurst and Megan Donahue and Holland Ford and Or Graur and Genevieve Graves and Stephanie Jouvel and Anton Koekemoer and Doron Lemze and Elinor Medezinski and Alberto Molino and Leonidas Moustakas and Sara Ogaz and Adam Riess and Steve Rodney and Piero Rosati and Keiichi Umetsu and Wei Zheng and Adi Zitrin and Matthias Bartelmann and Rychard Bouwens and Nicole Czakon and Ole Host and Leopoldo Infante and Saurabh Jha and Yolanda Jimenez-Teja and Daniel Kelson and Ofer Lahav and Ruth Lazkoz and Dani Maoz and Curtis McCully and Peter Melchior and Massimo Meneghetti and Julian Merten and John Moustakas and Mario Nonino and Brandon Patel and Eniko Regos and Stella Seitz and Jack Sayers and Sunil Golwala and Arjen Van der Wel},
journal= {arXiv preprint arXiv:1106.3328},
year = {2015}
}
Comments
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