CLUMP-3D: Three-dimensional Shape and Structure of 20 CLASH Galaxy Clusters from Combined Weak and Strong Lensing

• Published in: The Astrophysical journal 2018-06, Vol.860 (2), p.126
• Main Authors: Chiu, I-Non, Umetsu, Keiichi, Sereno, Mauro, Ettori, Stefano, Meneghetti, Massimo, Merten, Julian, Sayers, Jack, Zitrin, Adi
• Format: Article
• Language: English
• Subjects: Astrophysics; Axial stress; Computer simulation; cosmology: observations; dark matter; Galactic clusters; Galaxies; galaxies: clusters: general; gravitational lensing: strong; gravitational lensing: weak; Halos; Lower bounds; Mathematical models; Numerical simulations; Stars & galaxies; Three dimensional analysis
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/aac4a0

We perform a three-dimensional triaxial analysis of 16 X-ray regular and 4 high-magnification galaxy clusters selected from the CLASH survey by combining two-dimensional weak-lensing and central strong-lensing constraints. In a Bayesian framework, we constrain the intrinsic structure and geometry of each individual cluster assuming a triaxial Navarro-Frenk-White halo with arbitrary orientations, characterized by the mass , halo concentration , and triaxial axis ratios ( ), and investigate scaling relations between these halo structural parameters. From triaxial modeling of the X-ray-selected subsample, we find that the halo concentration decreases with increasing cluster mass, with a mean concentration of at the pivot mass . This is consistent with the result from spherical modeling, . Independently of the priors, the minor-to-major axis ratio of our full sample exhibits a clear deviation from the spherical configuration ( at with uniform priors), with a weak dependence on the cluster mass. Combining all 20 clusters, we obtain a joint ensemble constraint on the minor-to-major axis ratio of and a lower bound on the intermediate-to-major axis ratio of at the 2 level from an analysis with uniform priors. Assuming priors on the axis ratios derived from numerical simulations, we constrain the degree of triaxiality for the full sample to be at , indicating a preference for a prolate geometry of cluster halos. We find no statistical evidence for an orientation bias ( ), which is insensitive to the priors and in agreement with the theoretical expectation for the CLASH clusters.