scholarly journals Strong and Weak Lensing United II: the Cluster Mass Distribution of the Most X-ray Luminous Cluster RX J1347.5-1145

2005 ◽  
Author(s):  
M Bradac
Keyword(s):  
Mass Distribution ◽  
Weak Lensing ◽  
X Ray ◽  
Cluster Mass

scholarly journals Strong & Weak Lensing United: the Cluster Mass Distribution of RX J1347–1145

2004 ◽  
Vol 2004 (IAUS225) ◽  
pp. 155-160 ◽  
Author(s):  
M. Bradac ◽  
P. Schneider ◽  
T. Erben ◽  
M. Lombardi
Keyword(s):  
Mass Distribution ◽  
Weak Lensing ◽  
Cluster Mass

scholarly journals Weak-lensing mass calibration of the Sunyaev–Zel’dovich effect using APEX-SZ galaxy clusters

2018 ◽  
Vol 488 (2) ◽  
pp. 1728-1759 ◽  
Author(s):  
A Nagarajan ◽  
F Pacaud ◽  
M Sommer ◽  
M Klein ◽  
K Basu ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Accurate Determination ◽  
Sample Selection ◽  
Weak Lensing ◽  
Scaling Relations ◽  
Precision Data ◽  
X Ray ◽  
Cluster Mass ◽  
Direct Observations ◽  
Sunyaev Zel'dovich Effect

ABSTRACT The use of galaxy clusters as precision cosmological probes relies on an accurate determination of their masses. However, inferring the relationship between cluster mass and observables from direct observations is difficult and prone to sample selection biases. In this work, we use weak lensing as the best possible proxy for cluster mass to calibrate the Sunyaev–Zel’dovich (SZ) effect measurements from the APEX-SZ experiment. For a well-defined (ROSAT) X-ray complete cluster sample, we calibrate the integrated Comptonization parameter, YSZ, to the weak-lensing derived total cluster mass, M500. We employ a novel Bayesian approach to account for the selection effects by jointly fitting both the SZ Comptonization, YSZ–M500, and the X-ray luminosity, Lx–M500, scaling relations. We also account for a possible correlation between the intrinsic (lognormal) scatter of Lx and YSZ at fixed mass. We find the corresponding correlation coefficient to be $r= 0.47_{-0.35}^{+0.24}$, and at the current precision level our constraints on the scaling relations are consistent with previous works. For our APEX-SZ sample, we find that ignoring the covariance between the SZ and X-ray observables biases the normalization of the YSZ–M500 scaling high by 1–2σ and the slope low by ∼1σ, even when the SZ effect plays no role in the sample selection. We conclude that for higher precision data and larger cluster samples, as anticipated from on-going and near-future cluster cosmology experiments, similar biases (due to intrinsic covariances of cluster observables) in the scaling relations will dominate the cosmological error budget if not accounted for correctly.

scholarly journals CODEX Weak Lensing Mass Catalogue and implications on the mass-richness relation

2020 ◽  
Author(s):  
K Kiiveri ◽  
D Gruen ◽  
A Finoguenov ◽  
T Erben ◽  
L van Waerbeke ◽  
...  
Keyword(s):  
Large Scale ◽  
Mass Measurement ◽  
Weak Lensing ◽  
Bayesian Hierarchical ◽  
X Ray ◽  
Mass Scaling ◽  
Cluster Mass ◽  
Relation Model ◽  
Cluster Profiles ◽  
True Mass

Abstract The COnstrain Dark Energy with X-ray clusters (CODEX) sample contains the largest flux limited sample of X-ray clusters at 0.35 < z < 0.65. It was selected from ROSAT data in the 10,000 square degrees of overlap with BOSS, mapping a total number of 2770 high-z galaxy clusters. We present here the full results of the CFHT CODEX program on cluster mass measurement, including a reanalysis of CFHTLS Wide data, with 25 individual lensing-constrained cluster masses. We employ lensfit shape measurement and perform a conservative colour-space selection and weighting of background galaxies. Using the combination of shape noise and an analytic covariance for intrinsic variations of cluster profiles at fixed mass due to large scale structure, miscentring, and variations in concentration and ellipticity, we determine the likelihood of the observed shear signal as a function of true mass for each cluster. We combine 25 individual cluster mass likelihoods in a Bayesian hierarchical scheme with the inclusion of optical and X-ray selection functions to derive constraints on the slope α, normalization β, and scatter σln λ|μ of our richness–mass scaling relation model in log-space: <ln λ|μ > =αμ + β, with μ = ln (M200c/Mpiv), and Mpiv = 1014.81M⊙. We find a slope $\alpha = 0.49^{+0.20}_{-0.15}$, normalization $\exp (\beta ) = 84.0^{+9.2}_{-14.8}$ and $\sigma _{\ln \lambda | \mu } = 0.17^{+0.13}_{-0.09}$ using CFHT richness estimates. In comparison to other weak lensing richness-mass relations, we find the normalization of the richness statistically agreeing with the normalization of other scaling relations from a broad redshift range (0.0 < z < 0.65) and with different cluster selection (X-ray, Sunyaev-Zeldovich, and optical).

scholarly journals Reconciling galaxy cluster shapes, measured by theorists versus observers

2020 ◽  
Vol 500 (2) ◽  
pp. 2627-2644
Author(s):  
David Harvey ◽  
Andrew Robertson ◽  
Sut-Ieng Tam ◽  
Mathilde Jauzac ◽  
Richard Massey ◽  
...  
Keyword(s):  
Hubble Space Telescope ◽  
Orientation Angle ◽  
Galaxy Cluster ◽  
Galactic Nuclei ◽  
Weak Lensing ◽  
Strongly Correlated ◽  
The Bahamas ◽  
Cluster Galaxy ◽  
Moments Of Inertia ◽  
X Ray

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.

scholarly journals Weak lensing calibration of mass bias in the REFLEX+BCS X-ray galaxy cluster catalogue

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

scholarly journals A study on the relationship between internal nozzle geometry and injected mass distribution of eight ECN Spray G nozzles.

2017 ◽  
Author(s):  
Katarzyna E Matusik ◽  
Daniel J Duke ◽  
Nicholas Sovis ◽  
Andrew B Swantek ◽  
Christopher F Powell ◽  
...  
Keyword(s):  
Mass Distribution ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Gasoline Direct Injection ◽  
Nozzle Geometry ◽  
Hole Density ◽  
Full Spectrum ◽  
Length Scales ◽  
X Ray ◽  
The Relationship

Gasoline direct injection (GDI) nozzles are manufactured to meet geometric specifications with length scales onthe order of a few hundred microns. The machining tolerances of these nominal dimensions are not always knowndue to the difficulty in accurately measuring such small length scales in a nonintrusive fashion. To gain insight intothe variability of the machined dimensions as well as any effects that this variability may have on the fuel spraybehavior, a series of measurements of the internal geometry and fuel mass distribution were performed on a set ofeight nominally duplicate GDI “Spray G” nozzles provided by the Engine Combustion Network. The key dimensionsof each of the eight nozzle holes were measured with micron resolution using full spectrum x-ray tomographicimaging at the 7-BM beamline of the Advanced Photon Source at Argonne National Laboratory. Fuel densitydistributions at 2 mm downstream of the nozzle tips were obtained by performing x-ray radiography measurementsfor many lines of sight. The density measurements reveal nozzle-to-nozzle as well as hole-to-hole density variations.The combination of high-resolution geometry and fuel distribution datasets allows spray phenomena to be linked tospecific geometric characteristics of the nozzle, such as variability in the hole lengths and counterbore diameters,and the hole inlet corner radii. This analysis provides important insight into which geometrical characteristics ofthe nozzles may have the greatest importance in the development of the injected sprays, and to what degreethese geometric variations might account for the total spray variability. The goal of this work is then to further theunderstanding of the relationship between internal nozzle geometry and fuel injection, provide input to improvecomputational models, and ultimately aid in optimizing injector design for higher fuel efficiency and lower emissionsengines.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4766

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