Lensing and x-ray mass estimates of clusters (simulations)

By E. Rasia, Massimo Meneghetti, R. Martino, Stefano Borgani, A. Bonafede, Klaus Dolag, S. Ettori, D. Fabjan, Carlo Giocoli, P. Mazzotta and 3 more. 2012

187 citations recorded by the source corpus.

We present a comparison between weak-lensing and x-ray mass estimates of a sample of numerically simulated clusters. The sample consists of the 20 most massive objects at redshift z = 0.25 and Mvir > 5 × 1014M⊙ h−1. They were found in a cosmological simulation of volume 1 h−3 Gpc3, evolved in the framework of a WMAP-7 normalized cosmology. Each cluster has been resimulated at higher resolution and with more complex gas physics. We processed it through Skylens and X-MAS to generate optical and x-ray mock observations along three orthogonal projections. The final sample consists of 60 cluster realizations. The optical simulations include lensing effects on background sources. Standard observational tools and methods of analysis are used to recover the mass profiles of each cluster projection from the mock catalogue. The resulting mass profiles from lensing and x-ray are individually compared to the input mass distributions. Given the size of our sample, we could also investigate the dependence of the results on cluster morphology, environment, temperature inhomogeneity and mass. We confirm previous results showing that lensing masses obtained from the fit of the cluster tangential shear profiles with Navarro–Frenk–White functionals are biased low by ∼5–10% with a large scatter (∼10–25%). We show that scatter could be reduced by optimally selecting clusters either having regular morphology or living in substructure-poor environment. The x-ray masses are biased low by a large amount (∼25–35%), evidencing the presence of both non-thermal sources of pressure in the intra-cluster medium (ICM) and temperature inhomogeneity, but they show a significantly lower scatter than weak-lensing-derived masses. The x-ray mass bias grows from the inner to the outer regions of the clusters. We find that both biases are weakly correlated with the third-order power ratio, while a stronger correlation exists with the centroid shift. Finally, the x-ray bias is strongly connected with temperature inhomogeneities. Comparison with a previous analysis of simulations leads to the conclusion that the values of x-ray mass bias from simulations are still uncertain, showing dependences on the ICM physical treatment and, possibly, on the hydrodynamical scheme adopted.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/431fb86436fd1bf22be217016af082dfa819a627

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Citations in the corpus

CLASH: WEAK-LENSING SHEAR-AND-MAGNIFICATION ANALYSIS OF 20 GALAXY CLUSTERS (2014, background): “On average, this will lead to an underestimation of the cluster mass when spherical symmetry is assumed (Rasia et al. 2012).”
Masses of Galaxy Clusters from Gravitational Lensing (2013, background): “As discussed in Becker & Kravtsov (2011) and Rasia et al. (2012), the bias that is introduced depends on how the mass is inferred from the lensing signal.”
JOINT ANALYSIS OF CLUSTER OBSERVATIONS. II. CHANDRA/XMM-NEWTON X-RAY AND WEAK LENSING SCALING RELATIONS FOR A SAMPLE OF 50 RICH CLUSTERS OF GALAXIES (2012, background): “Rasia et al. (2012) consider a similar question; they examine whether the ratio of the X-ray mass to the true mass is correlated with centroid shift or power ratio.”
Weighing the Giants - I. Weak-lensing masses for 51 massive galaxy clusters: project overview, data analysis methods and cluster images (2012, background): “…even for the most dynamically relaxed clusters, and at optimal measurement radii (r ∼ r2500), hydrostatic X-ray mass estimates are expected to be biased at the 5–10% level due to non-thermal pressure support from residual gas bulk motion and other processes (Nagai et al. 2007; Rasia et al. 2012).”
Planck 2013 results. XX. Cosmology from Sunyaev-Zeldovich cluster counts (2013, methodology): “Estimates of biasing due to temperature inhomogeneities can range up to 10 or 15 percent (e.g., Rasia et al. 2012).”
THE DENSITY PROFILES OF MASSIVE, RELAXED GALAXY CLUSTERS. I. THE TOTAL DENSITY OVER THREE DECADES IN RADIUS (2012, background): “Mock observations of simulated clusters show that to a remarkable degree, X-ray observations are able to recover spherically-averaged mass profiles with a scatter of only ' 5%−10% (Nagai et al. 2007; Lau et al. 2009; Meneghetti et al. 2010b; Rasia et al. 2012).”
Towards a realistic population of simulated galaxy groups and clusters (2013, methodology): “We use the true M500 for the simulated systems in this comparison, c© 2014 RAS, MNRAS 000, 1–23 as weak lensing masses are thought to be biased on average by only a few per cent (e.g. Becker & Kravtsov 2011; Bahé, McCarthy & King 2012, but see Rasia et al. 2012 who find somewhat larger biases).”
The Frontier Fields lens modelling comparison project (2016, background): “…the cluster mass within the Einstein radius (∼ 100 kpc for a massive cluster) but the addition of further constraints at larger radii are required in order to appropriately measure the shape of the density profiles out to the cluster outskirts (Meneghetti et al. 2010a; Rasia et al. 2012).”
Cosmology and astrophysics from relaxed galaxy clusters - II. Cosmological constraints (2014, background): “A similar level of dispersion is expected due to nonthermal pressure (Nagai et al. 2007; Rasia et al. 2012; Nelson et al. 2014). tion for a decreasing trend with mass at radii ∼ r2500, and since marginalizing over an fgas–”
CLASH: JOINT ANALYSIS OF STRONG-LENSING, WEAK-LENSING SHEAR, AND MAGNIFICATION DATA FOR 20 GALAXY CLUSTERS (2015, background): “Numerical simulations suggest that these mass estimates tend to be biased low (by ∼ 5%–10%; see Meneghetti et al. 2010; Becker & Kravtsov 2011; Rasia et al. 2012) because local substructures that are abundant in cluster outskirts dilute the shear tangential to the cluster center.”