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

I. Non Chiu, Keiichi Umetsu, Mauro Sereno, Stefano Ettori, Massimo Meneghetti, Julian Merten, Jack Sayers, Adi Zitrin

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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 NavarroFrenkWhite halo with arbitrary orientations, characterized by the mass M200c, halo concentration c200c, and triaxial axis ratios (qa < qb), 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 c200c = 4.82 ± 0.30 at the pivot mass = M200c 1015 M h-1. This is consistent with the result from spherical modeling, c200c = 4.51 ± 0.14. Independently of the priors, the minor-to-major axis ratio qa of our full sample exhibits a clear deviation from the spherical configuration (qa = 0.52 ± 0.04 at 1015 M h-1 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 qa = 0.652-0.078+0.162 and a lower bound on the intermediate-to-major axis ratio of qb ≥ 0.63 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 T = 0.79 ± 0.03 at 1015 M h-1, indicating a preference for a prolate geometry of cluster halos. We find no statistical evidence for an orientation bias (fgeo = 0.93 ± 0.07), which is insensitive to the priors and in agreement with the theoretical expectation for the CLASH clusters.

Original languageAmerican English
Article number126
JournalAstrophysical Journal
Issue number2
StatePublished - 20 Jun 2018


  • cosmology: observations
  • dark matter
  • galaxies: clusters: general
  • gravitational lensing: strong
  • gravitational lensing: weak

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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