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 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=1015M⊙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 1015M⊙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 2σ
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 1015M⊙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)
(abridged)Comment: Accepted by the ApJ. This is one of the three companion papers,
including Umetsu et al. 2018 (arXiv:1804.00664) and Sereno et al. 2018
(arXiv:1804.00667), in the CLUMP-3D project. Go go go, HoHo