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

By Keiichi Umetsu, T. Broadhurst. 2007

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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 cvir = 13.4+ 5.3−3.3, lying far from the predicted value of cvir ∼ 5, corresponding to the measured virial mass, Mvir = (2.1 ± 0.2) × 1015 M☉, posing a challenge to the standard assumptions defining the ΛCDM 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 Mvir = (1.5–2.1) × 1015 M☉, and the combined ACS and Subaru 2D mass reconstruction yields a tight constraint on the concentration parameter, cvir = 12.7 ± 1 ± 2.8 (c200 ∼ 10), improving upon the statistical accuracy of our earlier 1D analysis. Importantly, our best-fitting profile properly reproduces the observed Einstein radius of 45'' (zs = 1), in contrast to other weak-lensing work, reporting lower concentration profiles, which underestimate the observed Einstein radius.

Subfields: Astronomy and Astrophysics, Instrumentation, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/d5928b29271895fe006364339bedebc58d38d4e4

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Citations in the corpus

New Multiply-Lensed Galaxies Identified in ACS/NIC3 Observations of Cl0024+1654, Using an Improved Mass Model (2009, methodology): “In Broadhurst et al. (2005b) we developed a model-independent method (see also Umetsu & Broadhurst 2008) for reconstructing the cluster mass profile using azimuthally-averaged WL shape distortion and magnification bias measurements, in the wide-field Subaru images.”
CONTRASTING GALAXY FORMATION FROM QUANTUM WAVE DARK MATTER, ψDM, WITH ΛCDM, USING PLANCK AND HUBBLE DATA (2015, background): “…in the number density of sources detected above a flux limit, which in the case of lensing clusters is well established (Broadhurst et al. 1995; Umetsu & Broadhurst 2008) and has led to the detection of the highest redshift and lowest luminosity galaxies currently known (Zheng et al. 2012; Coe…”
LoCuSS: Subaru Weak Lensing Study of 30 Galaxy Clusters (2009, methodology): “The mass density fields between different pixels in the mass map are highly correlated, so the correlations need to be properly taken into account when extracting some useful information from the mass map (e.g., Umetsu & Broadhurst 2008).”
Gravitational lensing (2010, background): “It is a puzzling and potentially highly important problem that strong-lensing analyses of galaxy clusters in many cases find that NFW density profiles well reproduce the observed image configurations, but with concentration parameters that are substantially larger than expected from numerical simula”
CLASH: JOINT ANALYSIS OF STRONG-LENSING, WEAK-LENSING SHEAR, AND MAGNIFICATION DATA FOR 20 GALAXY CLUSTERS (2015, methodology): “…can be magnified up into the flux-limited sample; this results in a net depletion of source counts (Taylor et al. 1998; Broadhurst et al. 2005; Umetsu & Broadhurst 2008; Umetsu et al. 2010, 2011b, 2012, 2014, 2015; Ford et al. 2012; Coe et al. 2012; Medezinski et al. 2013; Radovich et al.…”
Combined strong and weak lensing analysis of 28 clusters from the Sloan Giant Arcs Survey (2011, background): “…strong and weak lensing, have indicated that the mass distribution is surprisingly highly concentrated with an estimated concentration parameter of cvir ∼ 12, which is significantly higher than the expected standard ΛCDM prediction of cvir ∼ 4 (Broadhurst et al. 2005; Umetsu & Broadhurst 2008).”
CLASH: WEAK-LENSING SHEAR-AND-MAGNIFICATION ANALYSIS OF 20 GALAXY CLUSTERS (2014, methodology): “…used in combination with weak lensing shear to obtain a modelfree determination of the projected mass profiles of clusters (Schneider et al. 2000; Umetsu & Broadhurst 2008; Umetsu et al. 2011b; Umetsu 2013), effectively breaking degeneracies inherent in a standard weak-lensing analysis based on…”