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Clash: Weak-lensing shear-and-magnification analysis of 20 galaxy clusters

By Keiichi Umetsu, Elinor Medezinski, Mario Nonino, Julian Merten, Marc Postman, Massimo Meneghetti, Megan Donahue, Nicole Czakon, Alberto Molino, Stella Seitz, Daniel Gruen, Doron Lemze, Italo Balestra, Narciso Benítez, Andrea Biviano, Tom Broadhurst, Holland Ford, Claudio Grillo, Anton Koekemoer, Peter Melchior, Amata Mercurio, John Moustakas, Piero Rosati and Adi Zitrin


We present a joint shear-and-magnification weak-lensing analysis of a sample of 16 X-ray-regular and 4 high-magnification galaxy clusters at 0.19 <~ z <~ 0.69 selected from the Cluster Lensing And Supernova survey with Hubble (CLASH). Our analysis uses wide-field multi-color imaging, taken primarily with Suprime-Cam on the Subaru Telescope. From a stacked-shear-only analysis of the X-ray-selected subsample, we detect the ensemble-averaged lensing signal with a total signal-to-noise ratio of ~= 25 in the radial range of 200-3500 kpc h -1, providing integrated constraints on the halo profile shape and concentration-mass relation. The stacked tangential-shear signal is well described by a family of standard density profiles predicted for dark-matter-dominated halos in gravitational equilibrium, namely, the Navarro-Frenk-White (NFW), truncated variants of NFW, and Einasto models. For the NFW model, we measure a mean concentration of c200c=4.01+0.35-0.32 at an effective halo mass of M200c=1.34+0.10-0.09× 1015 M_⊙. We show that this is in excellent agreement with Λ cold dark matter (ΛCDM) predictions when the CLASH X-ray selection function and projection effects are taken into account. The best-fit Einasto shape parameter is α _E=0.191+0.071-0.068, which is consistent with the NFW-equivalent Einasto parameter of ~0.18. We reconstruct projected mass density profiles of all CLASH clusters from a joint likelihood analysis of shear-and-magnification data and measure cluster masses at several characteristic radii assuming an NFW density profile. We also derive an ensemble-averaged total projected mass profile of the X-ray-selected subsample by stacking their individual mass profiles. The stacked total mass profile, constrained by the shear+magnification data, is shown to be consistent with our shear-based halo-model predictions, including the effects of surrounding large-scale structure as a two-halo term, establishing further consistency in the context of the ΛCDM model

Topics: cosmology: observations, dark matter, galaxies: clusters: general, gravitational lensing: weak, Nuclear and High Energy Physics
Year: 2014
DOI identifier: 10.1088/0004-637X
OAI identifier: oai:iris.unife.it:11392/2333706
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