The Mass Structure of the Galaxy Cluster Cl0024+1654 from a Full Lensing Analysis of Joint Subaru and ACS/NIC3 Observations

TL;DR

This study combines deep Subaru and HST lensing data to accurately map the mass distribution of galaxy cluster Cl0024+1654, revealing a well-fitted NFW profile and insights into its post-merger dynamical state.

Contribution

It presents a comprehensive joint weak and strong lensing analysis of Cl0024+1654, providing the first consistent mass profile and independent mass constraints for this merging galaxy cluster.

Findings

Mass profile fits an NFW model with M_{vir} ≈ 1.2×10^{15} M_{sun}/h

Cluster is in a post-collision state consistent with a major line-of-sight merger

Full lensing analysis constrains total projected mass to (1.4 ± 0.3)×10^{15} M_{sun}/h

Abstract

We derive an accurate mass distribution of the rich galaxy cluster Cl0024+1654 (z=0.395) based on deep Subaru BR_{c}z' imaging and our recent comprehensive strong lensing analysis of HST/ACS/NIC3 observations. We obtain the weak lensing distortion and magnification of undilted samples of red and blue background galaxies by carefully combining all color and positional information. Unlike previous work, the weak and strong lensing are in excellent agreement where the data overlap. The joint mass profile continuously steepens out to the virial radius with only a minor contribution \sim 10% in the mass from known subcluster at a projected distance of \sim 700kpc/h. The projected mass distribution for the entire cluster is well fitted with a single Navarro-Frenk-White model with a virial mass, M_{vir} = (1.2 \pm 0.2) \times 10^{15} M_{sun}/h, and a concentration, c_{vir} = 9.2^{+1.4}_{-1.2}. This model fit is fully consistent with the depletion of the red background counts, providing independent confirmation. Careful examination and interpretation of X-ray and dynamical data strongly suggest that this cluster system is in a post collision state, which we show is consistent with our well-defined mass profile for a major merger occurring along the line of sight, viewed approximately 2-3Gyr after impact when the gravitational potential has had time to relax in the center, before the gas has recovered and before the outskirts are fully virialized. Finally, our full lensing analysis provides a model-independent constraint of M_{2D}(<r_{vir}) = (1.4 \pm 0.3) \times 10^{15} M_{sun}/h for the projected mass of the whole system, including any currently unbound material beyond the virial radius, which can constrain the sum of the two pre-merger cluster masses when designing simulations to explore this system.