Weighing simulated galaxy clusters using lensing and X-ray

By Massimo Meneghetti, E. Rasia, Julian Merten, F. Bellagamba, S. Ettori, P. Mazzotta, Klaus Dolag, Saloua El Marri. 2009

229 citations recorded by the source corpus.

Context. Measuring the mass of galaxy clusters is a key issue in cosmology. Among the methods employed to achieve this goal, the techniques based on lensing and X-ray analyses are perhaps the most widely used. However, the comparison between these mass estimates is often di cult and, in several clusters, the results apparently are inconsistent. Aims. We aim at investigating potential biases in lensing and X-ray methods to measure the cluster mass profiles. Methods. We do so by performing realistic simulations of lensing and X-ray observations that are subsequently analyzed using observational techniques. The resulting mass estimates are compared among them and with the input models. Three clusters obtained from state-of-the-art hydrodynamical simulations, each of which has been projected along three independent lines-of-sight, are used for this analysis. Results. We find that strong lensing models can be trusted over a limited region around the cluster core. Extrapolating the strong lensing mass models to outside the Einstein ring can lead to significant biases in the mass estimates , if the BCG is not modeled properly for example. Weak lensing mass measurements can be largely a ected by substructures, depending on the method implemented to convert the shear into a mass estimate. Using non-parametric methods which combine weak and strong lensing data, the projected masses within R200 can be constrained with a precision of 10%. De-projection of lensing masses increases the scatter around the true masses by more than a factor of two due to cluster triaxiality. X-ray mass measurements have much smaller scatter (about a factor of two smaller than the lensing masses) but they are generally biased low by 5 20%. This bias is entirely ascribable to bulk motions in the gas of our simulated clusters. Using the lensing and the X-ray masses as proxies for the true and the hydrostatic equilibrium masses of the simulated clusters and by averaging over the cluster sample we are able to measure the lack of hydrostatic equilibrium in the systems we have investigated. Conclusions. Although the comparison between lensing and X-ray masses may be di cult in individual systems due to triaxiality and substructures, using a large number of clusters with both lensing and X-ray observations may lead to important information about their gas physics and allow to use lensing masses to calibrate the X-ray scaling relations.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/ddbfb480e9f1c2e548f5cc685f454293a241c31d

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Citations in the corpus

Weighing the Giants - I. Weak-lensing masses for 51 massive galaxy clusters: project overview, data analysis methods and cluster images (2012, background): “However, because clusters are generally triaxial, the assumption of spherical symmetry leads to over-/underestimates of the mass if the cluster major axis is aligned along/perpendicular to the line of sight (Corless & King 2007; Meneghetti et al. 2010).”
Lensing and x-ray mass estimates of clusters (simulations) (2012, methodology): “If our clusters were chosen for their lensing signals, and in particular for strong-gravitational lensing, we would have had more objects strongly aligned along the line of sight (e.g. Meneghetti et al. 2010).”
Jet-regulated cooling catastrophe (2010, background): “This is predicted to have severe consequences when simulating the gravitational lensing effect of such structures (Peirani et al. 2008; Meneghetti et al. 2010).”
CLASH: WEAK-LENSING SHEAR-AND-MAGNIFICATION ANALYSIS OF 20 GALAXY CLUSTERS (2014, background): “…properties can introduce an orientation bias in favor of prolate structure pointed to the observer, as this orientation boosts the projected mass density, and a selection bias toward intrinsically over-concentrated clusters (Broadhurst et al. 2008; Oguri et al. 2009; Meneghetti et al. 2010a).”
Masses of Galaxy Clusters from Gravitational Lensing (2013, methodology): “For instance, Meneghetti et al. (2010) focused specifically on the comparison of lensing masses and X-ray estimates using hydrodynamical simulations.”
Planck 2013 results. XX. Cosmology from Sunyaev-Zeldovich cluster counts (2013, background): “…to underestimate the true mass by 10–15 percent due to neglect of bulk motions and turbulence in the intra-cluster medium (ICM, e.g., Nagai et al. 2007; Piffaretti & Valdarnini 2008; Meneghetti et al. 2010), an effect that is commonly referred to in the literature as the “hydrostatic mass bias”.”
The Frontier Fields lens modelling comparison project (2016, methodology): “…the weak lensing regime (e.g. for Subaru-like observations), the grid or light-rays covers a much wider area (∼ 8×8 h−2Mpc2); • Using our code GLFAST (Meneghetti et al. 2010a), we compute the total deflection α(x) at each light-ray position x, accounting for the contributions from all particles…”
The MCXC: a meta-catalogue of x-ray detected clusters of galaxies (2010, background): “…has also been made in understanding the systematics affecting X-ray mass estimates via simulations (e.g., Rasia et al. 2006; Nagai et al. 2007a; Piffaretti & Valdarnini 2008) and via combination with gravitational lensing (e.g., Mahdavi et al. 2008; Zhang et al. 2010; Meneghetti et al. 2010).”
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, methodology): “We choose to standardize the bulk of our discussion on the weak lensing overdensity radius rWL500 , because lensing masses are likely to be more unbiased for non-relaxed clusters (Meneghetti et al. 2010).”
Observational probes of cosmic acceleration (2012, background): “Unfortunately, hydrostatic mass estimates are themselves problematic because non-thermal pressure support (bulk motions, magnetic fields, cosmic rays) is expected to bias them at the ≈ 10%− 20% level (Lau et al., 2009; Meneghetti et al., 2010), and it is not clear that these biases can be predicted ”
THE ATACAMA COSMOLOGY TELESCOPE: COSMOLOGY FROM GALAXY CLUSTERS DETECTED VIA THE SUNYAEV–ZEL'DOVICH EFFECT (2010, background): “…from cosmic rays to be about 5%–10% (Jubelgas et al. 2008; Pfrommer & Enßlin 2004) and from turbulent pressure to be between 5% and 20% (Lau et al. 2009; Meneghetti et al. 2010; Burns et al. 2010), with only the latter work suggesting levels as high as 20% and that largely at the cluster outskirts.”
Cosmological Parameters from Observations of Galaxy Clusters (2011, methodology): “In combination with weak lensing, strong lensing constraints can improve significantly the absolute calibration of projected mass maps (e.g. Bradač et al. 2005, 2006; Meneghetti et al. 2010).”
ON THE ACCURACY OF WEAK-LENSING CLUSTER MASS RECONSTRUCTIONS (2010, background): “…et al. 2006; Shaw et al. 2006; Bett et al. 2007; Macciò et al. 2007, 2008) can bias a spherically-symmetric model fit of the reduced tangential shear profile and lead to errors of≈±30− 50% in the estimated mass (Clowe et al. 2004; Oguri et al. 2005; Corless & King 2007; Meneghetti et al. 2010b).”
X-RAY PROPERTIES OF THE FIRST SUNYAEV–ZEL'DOVICH EFFECT SELECTED GALAXY CLUSTER SAMPLE FROM THE SOUTH POLE TELESCOPE (2010, background): “Numerical simulations have suggested that hydrostatic mass estimates could be biased low by ∼10% due to additional non-thermal pressure support of the gas in clusters (e.g., Lau et al. 2009; Meneghetti et al. 2010).”
Creation of cosmic structure in the complex galaxy cluster merger Abell 2744 (2011, methodology): “This method has been extensively tested in Meneghetti et al. (2010) and proved its capability to faithfully recover the cluster mass distribution over a broad range of scales.”
THE DENSITY PROFILES OF MASSIVE, RELAXED GALAXY CLUSTERS. I. THE TOTAL DENSITY OVER THREE DECADES IN RADIUS (2012, background): “…bias suggest that the population of cluster lenses may have ' 10%− 35% higher concentrations on average (Hennawi et al. 2007; Fedeli et al. 2007; Meneghetti et al. 2010b), but that highest concentrations seen in MS2137 and other clusters (e.g., Broadhurst et al. 2008; Zitrin et al. 2011a) are…”
Weighing the Giants – III. Methods and measurements of accurate galaxy cluster weak-lensing masses (2012, methodology): “Meneghetti et al. (2010) show that the use of aperture-mass method with such NFW corrections can lead to a similar bias as directly fitting an NFW profile to a large radial range.”
GALAXY CLUSTERS SELECTED WITH THE SUNYAEV–ZEL'DOVICH EFFECT FROM 2008 SOUTH POLE TELESCOPE OBSERVATIONS (2010, methodology): “The mass dependence of their pressure profile was determined using cluster mass estimates derived from the equation of hydrostatic equilibrium; simulations suggest that this method may underestimate the true mass by 10%–20% (Rasia et al. 2004; Meneghetti et al. 2010; Lau et al. 2009).”