scholarly journals Weighing the Giants – III. Methods and measurements of accurate galaxy cluster weak-lensing masses

2014 ◽  
Vol 439 (1) ◽  
pp. 48-72 ◽  
Author(s):  
Douglas E. Applegate ◽  
Anja von der Linden ◽  
Patrick L. Kelly ◽  
Mark T. Allen ◽  
Steven W. Allen ◽  
...  
Keyword(s):  
2020 ◽  
Vol 500 (2) ◽  
pp. 2627-2644
Author(s):  
David Harvey ◽  
Andrew Robertson ◽  
Sut-Ieng Tam ◽  
Mathilde Jauzac ◽  
Richard Massey ◽  
...  

ABSTRACT If properly calibrated, the shapes of galaxy clusters can be used to investigate many physical processes: from feedback and quenching of star formation, to the nature of dark matter. Theorists frequently measure shapes using moments of inertia of simulated particles’. We instead create mock (optical, X-ray, strong-, and weak-lensing) observations of the 22 most massive ($\sim 10^{14.7}\, \mathrm{ M}_\odot$) relaxed clusters in the BAHAMAS simulations. We find that observable measures of shape are rounder. Even when moments of inertia are projected into 2D and evaluated at matched radius, they overestimate ellipticity by 56 per cent (compared to observable strong lensing) and 430 per cent (compared to observable weak lensing). Therefore, we propose matchable quantities and test them using observations of eight relaxed clusters from the Hubble Space Telescope (HST) and Chandra X-Ray Observatory. We also release our HST data reduction and lensing analysis software to the community. In real clusters, the ellipticity and orientation angle at all radii are strongly correlated. In simulated clusters, the ellipticity of inner (<rvir/20) regions becomes decoupled: for example, with greater misalignment of the central cluster galaxy. This may indicate overly efficient implementation of feedback from active galactic nuclei. Future exploitation of cluster shapes as a function of radii will require better understanding of core baryonic processes. Exploitation of shapes on any scale will require calibration on simulations extended all the way to mock observations.


2016 ◽  
Vol 466 (3) ◽  
pp. 3663-3673 ◽  
Author(s):  
Melanie Simet ◽  
Nicholas Battaglia ◽  
Rachel Mandelbaum ◽  
Uroš Seljak
Keyword(s):  
X Ray ◽  

2021 ◽  
Vol 508 (1) ◽  
pp. 1280-1295
Author(s):  
Elizabeth J Gonzalez ◽  
Cinthia Ragone-Figueroa ◽  
Carlos J Donzelli ◽  
Martín Makler ◽  
Diego García Lambas ◽  
...  

ABSTRACT We present a detailed study of the shapes and alignments of different galaxy cluster components using hydrodynamical simulations. We compute shape parameters from the dark matter (DM) distribution, the galaxy members and the intracluster light (ICL). We assess how well the DM cluster shape can be constrained by means of the identified galaxy member positions and the ICL. Further, we address the dilution factor introduced when estimating the cluster elongation using weak-lensing stacking techniques, which arises due to the misalignment between the total surface mass distribution and the distribution of luminous tracers. The dilution is computed considering the alignment between the DM and the brightest cluster galaxy, the galaxy members and the ICL. Our study shows that distributions of galaxy members and ICL are less spherical than the DM component, although both are well aligned with the semimajor axis of the latter. We find that the distribution of galaxy members hosted in more concentrated subhaloes is more elongated than the distribution of the DM. Moreover, these galaxies are better aligned with the DM component compared to the distribution of galaxies hosted in less concentrated subhaloes. We conclude that the positions of galaxy members can be used as suitable tracers to estimate the cluster surface density orientation, even when a low number of members is considered. Our results provide useful information for interpreting the constraints on the shapes of galaxy clusters in observational studies.


2007 ◽  
Vol 467 (2) ◽  
pp. 427-436 ◽  
Author(s):  
S. Paulin-Henriksson ◽  
V. Antonuccio-Delogu ◽  
C. P. Haines ◽  
M. Radovich ◽  
A. Mercurio ◽  
...  

Author(s):  
S Grandis ◽  
J J Mohr ◽  
J P Dietrich ◽  
S Bocquet ◽  
A Saro ◽  
...  

Abstract We forecast the impact of weak lensing (WL) cluster mass calibration on the cosmological constraints from the X-ray selected galaxy cluster counts in the upcoming eROSITA survey. We employ a prototype cosmology pipeline to analyze mock cluster catalogs. Each cluster is sampled from the mass function in a fiducial cosmology and given an eROSITA count rate and redshift, where count rates are modeled using the eROSITA effective area, a typical exposure time, Poisson noise and the scatter and form of the observed X-ray luminosity– and temperature–mass–redshift relations. A subset of clusters have mock shear profiles to mimic either those from DES and HSC or from the future Euclid and LSST surveys. Using a count rate selection, we generate a baseline cluster cosmology catalog that contains 13k clusters over 14,892 deg2 of extragalactic sky. Low mass groups are excluded using raised count rate thresholds at low redshift. Forecast parameter uncertainties for ΩM, σ8 and w are 0.023 (0.016; 0.014), 0.017 (0.012; 0.010), and 0.085 (0.074; 0.071), respectively, when adopting DES+HSC WL (Euclid; LSST), while marginalizing over the sum of the neutrino masses. A degeneracy between the distance–redshift relation and the parameters of the observable–mass scaling relation limits the impact of the WL calibration on the w constraints, but with BAO measurements from DESI an improved determination of w to 0.043 becomes possible. With Planck CMB priors, ΩM (σ8) can be determined to 0.005 (0.007), and the summed neutrino mass limited to ∑mν < 0.241 eV (at 95%). If systematics on the group mass scale can be controlled, the eROSITA group and cluster sample with 43k objects and LSST WL could constrain ΩM and σ8 to 0.007 and w to 0.050.


2011 ◽  
Vol 411 (4) ◽  
pp. 2667-2694 ◽  
Author(s):  
M. Lerchster ◽  
S. Seitz ◽  
F. Brimioulle ◽  
R. Fassbender ◽  
M. Rovilos ◽  
...  

2019 ◽  
Vol 490 (2) ◽  
pp. 2606-2626 ◽  
Author(s):  
Hao-Yi Wu ◽  
David H Weinberg ◽  
Andrés N Salcedo ◽  
Benjamin D Wibking ◽  
Ying Zu

ABSTRACT Next-generation optical imaging surveys will revolutionize the observations of weak gravitational lensing by galaxy clusters and provide stringent constraints on growth of structure and cosmic acceleration. In these experiments, accurate modelling of covariance matrices of cluster weak lensing plays the key role in obtaining robust measurements of the mean mass of clusters and cosmological parameters. We use a combination of analytical calculations and high-resolution N-body simulations to derive accurate covariance matrices that span from the virial regime to linear scales of the cluster-matter cross-correlation. We validate this calculation using a public ray-tracing lensing simulation and provide a software package for calculating covariance matrices for a wide range of cluster and source sample choices. We discuss the relative importance of shape noise and density fluctuations, the impact of radial bin size, and the impact of off-diagonal elements. For a weak lensing source density ns = 10 arcmin−2, shape noise typically dominates the variance on comoving scales $r_{\rm p}\lesssim 5\ h^{-1} \, \rm Mpc$. However, for ns = 60 arcmin−2, potentially achievable with future weak lensing experiments, density fluctuations typically dominate the variance at $r_{\rm p}\gtrsim 1\ h^{-1} \, \rm Mpc$ and remain comparable to shape noise on smaller scales.


2014 ◽  
Vol 797 (2) ◽  
pp. 106 ◽  
Author(s):  
Ho Seong Hwang ◽  
Margaret J. Geller ◽  
Antonaldo Diaferio ◽  
Kenneth J. Rines ◽  
H. Jabran Zahid

2007 ◽  
Vol 3 (S244) ◽  
pp. 374-375
Author(s):  
Leila C. Powell ◽  
Scott T. Kay ◽  
Arif Babul ◽  
Andisheh Mahdavi

AbstractVarious differences in galaxy cluster properties derived from X-ray and weak lensing observations have been highlighted in the literature. One such difference is the observation of mass concentrations in lensing maps which have no X-ray counterparts (e.g. Jee, White, Ford et al. 2005). We investigate this issue by identifying substructures in maps of projected total mass (analogous to weak lensing mass reconstructions) and maps of projected X-ray surface brightness for three simulated clusters. We then compare the 2D mass substructures with both 3D subhalo data and the 2D X-ray substructures. Here we present preliminary results from the first comparison, where we have assessed the impact of projecting the data on subhalo identification.


2019 ◽  
Vol 488 (2) ◽  
pp. 1704-1727 ◽  
Author(s):  
Matthias Klein ◽  
Holger Israel ◽  
Aarti Nagarajan ◽  
Frank Bertoldi ◽  
Florian Pacaud ◽  
...  

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 sub-sample of 27 clusters, are optimized 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 multicolour 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 sub-fields of the COSMOS survey for different cluster redshift and magnitude limits. We measure a standard deviation of ∼6 per cent 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 per cent for deep, R = 26 mag, observations. This corresponds to 8.4 per cent and 1.4 per cent scatter in M200. Our background selection reduces this scatter by 20−40 per cent, 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.


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