Weak lensing measurements of the APEX-SZ galaxy cluster sample

Abstract

We present a weak lensing analysis for galaxy clusters from the APEX-SZ survey. For 39 massive galaxy clusters that were observed via the Sunyaev-Zel'dovich effect (SZE) with the APEX telescope, we analyse deep optical imaging data from WFI(@2.2mMPG/ESO) and Suprime-Cam(@SUBARU) in three bands. The masses obtained in this study, including an X-ray selected subsample of 27 clusters, are optimised for and used in studies constraining the mass to observable scaling relations at fixed cosmology. A novel focus of our weak lensing analysis is the multi-colour background selection to suppress effects of cosmic variance on the redshift distribution of source galaxies. We investigate the effects of cluster member contamination through galaxy density, shear profile, and recovered concentrations. We quantify the impact of variance in source redshift distribution on the mass estimate by studying nine subfields of the COSMOS survey for different cluster redshift and manitude limits. We measure a standard deviation of ∼ 6% on the mean angular diameter distance ratio for a cluster at z = 0.45 and shallow imaging data of R ≈ 23 mag. It falls to ∼ 1% for deep, R = 26 mag, observations. This corresponds to 8.4% and 1.4% scatter in M 200 . Our background selection reduces this scatter by 20 − 40%, depending on cluster redshift and imaging depth. We derived cluster masses with and without using a mass concentration relation and find consistent results, and concentrations consistent with the used mass-concentration relation.

Weak-lensing Analysis of X-Ray-selected XXL Galaxy Groups and Clusters with Subaru HSC Data

“…Weak-lensing observations in the cluster regime have established that the total matter distribution within clusters in projection can be well described by cuspy, outward steepening density profiles (Umetsu et al 2011b(Umetsu et al , 2014(Umetsu et al , 2016Newman et al 2013;Okabe et al 2013), with a near-universal shape (Niikura et al 2015;Umetsu & Diemer 2017), as predicted for collisionless halos in quasi-gravitational equilibrium (e.g., Navarro et al 1996Navarro et al , 1997Taylor & Navarro 2001;). Subsequent cluster lensing studies targeting lensing-unbiased samples (e.g., Merten et al 2015;Du et al 2015;Umetsu et al 2016;Okabe & Smith 2016;Cibirka et al 2017;Klein et al 2019) have found that the degree of mass concentration derived for these clusters agrees well with theoretical models calibrated for recent ΛCDM cosmologies (e.g., Bhattacharya et al 2013;Dutton & Macciò 2014;Meneghetti et al 2014;Diemer & Kravtsov 2015). The three-dimensional shapes of galaxy clusters as constrained by weak-lensing and multiwavelength data sets are found to be in agreement with ΛCDM predictions (e.g., Oguri et al 2005;Morandi et al 2012;Sereno et al , 2018Umetsu et al 2015).…”

Cluster–galaxy weak lensing

“…Since galaxy clusters are, on average, dynamically young and still growing through accretion and mergers, cluster halos are expected to have relatively low concentrations, c 200c ðz ¼ 0Þ $ 4, in contrast to individual galaxy halos that have denser central regions, c 200c ðz ¼ 0Þ $ 7 À 8 (Bhattacharya et al 2013;Dutton and Macciò 2014;Diemer and Kravtsov 2015;Child et al 2018;Diemer and Joyce 2019). These general trends are complicated by diverse formation and assembly histories of individual halos (Ludlow et al 2013), which translate into substantial scatter in the c-M relation, with a lognormal intrinsic dispersion of r int ðln c 200c Þ $ 35% 20 at fixed halo mass (e.g., Duffy et al 2008;Bhattacharya et al 2013;Diemer and Kravtsov 2015) 21 On the observational side, cluster lensing studies targeting lensing-unbiased samples (e.g., Merten et al 2015;Du et al 2015;Umetsu et al 2016Umetsu et al , 2020Okabe and Smith 2016;Cibirka et al 2017;Klein et al 2019) have found that the c-M relations derived for these cluster samples agree well with theoretical models calibrated for recent KCDM cosmologies (e.g., Bhattacharya et al 2013;Dutton and Macciò 2014;Meneghetti et al 2014;Diemer and Kravtsov 2015;Child et al 2018;Diemer and Joyce 2019).…”

Timing the last major merger of galaxy clusters with large halo sparsity

“…Abell 383 is a cluster at 𝑧 = 0.187 that has been observed in X-ray (Böhringer et al 2004;Vikhlinin et al 2006) and optical bands (Miyazaki et al 2002;Postman et al 2012) with numerous studies devoted to measurements of the cluster mass from gravitational lensing analyses (e.g. Okabe & Smith 2016;Umetsu et al 2016;Klein et al 2019). The cluster appears to be a relaxed system with HE masses 𝑀 500𝑐 = (3.10 ± 0.32) • 10 14 𝑀 and 𝑀 2500𝑐 = (1.68 ± 0.15) • 10 14 𝑀 from Chandra X-ray observations (Vikhlinin et al 2006), corresponding to the halo sparsity 𝑠 500,2500 = 1.84±0.25 that is close to the median of the halo sparsity distribution.…”