Combining Lens Distortion and Depletion to Map the Mass Distribution of A1689

Abstract

We derive a projected 2D mass map of the well-studied galaxy cluster A1689 based on an entropy-regularized maximum likelihood combination of the lens magnification and distortion of red background galaxies registered in deep Subaru images. The method is not restricted to the weak regime but applies to the whole area outside the tangential critical curve, where nonlinearity between the surface mass density and the observables extends to a radius of a few arcminutes. The known strong-lensing information is also readily incorporated in this approach, represented as a central pixel with a mean surface density close to the critical value. We also utilize the distortion measurements to locally downweight the intrinsic clustering noise, which otherwise perturbs the depletion signal. The projected mass profile continuously steepens with radius and is well fitted by the Navarro-Frenk-White model, but with a surprisingly large concentration c vir ¼ 13:4 þ5:3 À3:3 , lying far from the predicted value of c vir $ 5, corresponding to the measured virial mass, M vir ¼ (2:1 AE 0:2) ; 10 15 M , posing a challenge to the standard assumptions defining the ÃCDM model. We examine the consistency of our results with estimates derived with the standard weak-lensing estimators and by comparison with the inner mass profile obtained from strong lensing. All the reconstructions tested here imply a virial mass in the range M vir ¼ (1:5Y2:1) ; 10 15 M , and the combined ACS and Subaru 2D mass reconstruction yields a tight constraint on the concentration parameter, c vir ¼ 12:7 AE 1 AE 2:8 (c 200 $ 10), improving upon the statistical accuracy of our earlier 1D analysis. Importantly, our best-fitting profile properly reproduces the observed Einstein radius of 45 00 (z s ¼ 1), in contrast to other weak-lensing work, reporting lower concentration profiles, which underestimate the observed Einstein radius.

The strongest gravitational lenses

“…More precisely, the largest observed Einstein radii (e.g. Halkola et al 2008;Umetsu & Broadhurst 2008;Zitrin et al 2011) were claimed to exceed the maximum possible expectations of the standard cosmological model (Broadhurst & Barkana 2008;Oguri & Blandford 2009;Meneghetti et al 2011). These conclusions were drawn by either comparing the largest observed Einstein radii to those found in numerical simulations or by semi-analytically estimating the probability of finding the strongest observed lens systems in a ΛCDM universe.…”

Spherical collapse model and cluster formation beyond theΛcosmology: Indications for a clustered dark energy?

“…The concentration parameter c vir is an observable characteristic of the halo profile and is defined as c vir = r vir /r s where r vir is the virial radius of the system [77,78,79]. Dark matter profiles of clusters may be determined using lens distortion and magnification [41,80]. Such profiles have been recently obtained [41] for four clusters using the wide-field camera SuprimeCam [81] of the Subaru 8.3m telescope.…”

SUZAKUOBSERVATION OF A1689: ANISOTROPIC TEMPERATURE AND ENTROPY DISTRIBUTIONS ASSOCIATED WITH THE LARGE-SCALE STRUCTURE

“…In particular, the Subaru/Suprime-Cam is the best instrument to conduct the weak lensing analysis (e.g. Miyazaki et al 2002;Hamana et al 2003;Broadhurst et al 2005b;Umetsu & Broadhurst 2008;Umetsu et al 2009a,b;Hamana et al 2009;Okabe & Umetsu 2008;Okabe et al 2009;Oguri et al 2009), thanks to its high photon-collecting power and high imaging quality, combined with a wide field-of-view.…”