Detection of universality of dark matter profile from Subaru weak lensing measurements of 50 massive clusters

Abstract

We develop a novel method of measuring the lensing distortion profiles of clusters with stacking the "scaled" amplitudes of background galaxy ellipticities as a function of the "scaled" centric radius according to the Navarro-Frenk-White (NFW) prediction of each cluster, based on the assumption that the different clusters in a sample follow the universal NFW profile. First we demonstrate the feasibility of this method using both the analytical NFW model and simulated halos in a suite of high-resolution N-body simulations. We then apply, as a proof of concept, this method to the Subaru weak lensing data and the XMM/Chandra X-ray observables for a sample of 50 massive clusters in the redshift range 0.15 ≤ z ≤ 0.3, where their halo masses differ from each other by up to a factor of 10. To estimate the NFW parameters of each cluster, we use the halo mass proxy relation of X-ray observables, based on either the hydrostatic equilibrium or the gas mass, and then infer the halo concentration from the model scaling relation of halo concentration with halo mass. We evaluate a performance of the NFW scaling analysis by measuring the scatters of 50 cluster lensing profiles relative to the NFW predictions over a range of radii, 0.14 ≤ R/[h −1 Mpc] ≤ 2.8. We found a 4 -6σ level evidence of the universal NFW profile in 50 clusters, for both the X-ray halo mass proxy relations, although the gas mass appears to be a better proxy of the underlying true mass. By comparing the measurements with the simulations of cluster lensing profiles taking into account the statistical errors of intrinsic galaxy shapes in the Subaru data, we argue that additional halo mass errors or intrinsic scatters of σ(M 500c )/M 500c ∼ 0.2 -0.3 could reconcile a difference between the measurements and the simulations. This method allows us to some extent to preserve characteristics of individual clusters in the statistical weak lensing analysis, thereby yielding a new means of exploiting the underlying genuine form of the halo mass profile and the halo mass proxy relations via weak lensing information, under the assumption of the existence of the universal profile.

Clash: Joint Analysis of Strong-Lensing, Weak-Lensing Shear, and Magnification Data for 20 Galaxy Clusters*

“…Interpreting the effective mass from stacked lensing requires caution when the cluster sample spans a broad range of masses and redshifts (Mandelbaum et al 2005;Niikura et al 2015). If there is a significant scatter in the luminositymass relation of halos, then the halo mass distribution of a luminosity-selected sample becomes significantly broader, with the width and asymmetry of the distribution typically increasing for higher luminosity bins.…”

LoCuSS: weak-lensing mass calibration of galaxy clusters

“…Stacking the shear signal from a sample of clusters averages over the distribution of internal structures and halo triaxiality, and thus overcomes the structural biases suffered by some individual cluster mass measurements (e.g. Mandelbaum et al 2006;Johnston et al 2007;Okabe et al 2010aOkabe et al , 2013Umetsu et al 2011Umetsu et al , 2014Umetsu et al , 2015bOguri et al 2012;Leauthaud et al 2012;Miyatake et al 2013;Niikura et al 2015). We compute the average lensing signal in physical length unit centered on the respective BCGs.…”

The Projected Dark and Baryonic Ellipsoidal Structure of 20 CLASH Galaxy Clusters*

“…We model the radial mass distribution in galaxy clusters with a Navarro−Frenk−White (NFW) density profile, motivated by cosmological N-body simulations (Navarro et al 1996(Navarro et al , 1997 as well as by direct lensing observations (e.g., Newman et al 2013;Okabe et al 2013;Umetsu et al 2014Umetsu et al , 2016Niikura et al 2015;Umetsu & Diemer 2017). The radial dependence of the spherical NFW density profile is given by (Navarro et al 1996) The surface mass density Σ(R) as a function of projected clustercentric radius R is given by projecting ρ(r) along the line of sight.…”

“…Cluster lensing observations have established that the projected total mass distribution within individual and ensemble-averaged clusters can be well described by sharply steepening density profiles (Umetsu et al 2011a(Umetsu et al , 2014Newman et al 2013;Okabe et al 2013;, with a near-universal shape (Niikura et al 2015;Umetsu & Diemer 2017), as predicted for halos dominated by collisionless DM in quasi-gravitational equilibrium (e.g., Navarro et al 1996Navarro et al , 1997. Subsequent cluster lensing studies targeting lensing-unbiased samples (Du et al 2015;Merten et al 2015;Umetsu et al 2016;Cibirka et al 2017) have shown that the degree of halo concentration derived for these clusters agrees well with theoretical models that are calibrated for recent ΛCDM cosmologies with a relatively high normalization (Bhattacharya et al 2013;Dutton & Macciò 2014;Meneghetti et al 2014;Diemer & Kravtsov 2015).…”