Measuring the Mass Distribution in Galaxy Clusters

Geller, Margaret J.; Diaferio, Antonaldo; Rines, Kenneth J.; Serra, Ana Laura

doi:10.1088/0004-637x/764/1/58

Cited by 67 publications

(96 citation statements)

References 65 publications

(154 reference statements)

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“…We chose this sample size as it reflects the scale of data we have today for measuring both weak-lensing profiles and also with significant spectroscopic follow-up [40][41][42].…”

Section: Systematicsmentioning

confidence: 99%

Probing theories of gravity with phase space-inferred potentials of galaxy clusters

et al. 2016

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Modified theories of gravity provide us with a unique opportunity to generate innovative tests of gravity. In Chameleon f (R) gravity, the gravitational potential differs from the weak-field limit of general relativity (GR) in a mass dependent way. We develop a probe of gravity which compares high mass clusters, where Chameleon effects are weak, to low mass clusters, where the effects can be strong. We utilize the escape velocity edges in the radius/velocity phase space to infer the gravitational potential profiles on scales of 0.3 -1 virial radii. We show that the escape edges of low mass clusters are enhanced compared to GR, where the magnitude of the difference depends on the background field value |fR0|. We validate our probe using N-body simulations and simulated light cone galaxy data. For a DESI (Dark Energy Spectroscopic Instrument) Bright Galaxy Sample, including observational systematics, projection effects, and cosmic variance, our test can differentiate between GR and Chameleon f (R) gravity models, |fR0| = 4 × 10 −6 (2 × 10 −6 ) at > 5σ (> 2σ), more than an order of magnitude better than current cluster-scale constraints.

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“…We chose this sample size as it reflects the scale of data we have today for measuring both weak-lensing profiles and also with significant spectroscopic follow-up [40][41][42].…”

Section: Systematicsmentioning

confidence: 99%

Probing theories of gravity with phase space-inferred potentials of galaxy clusters

et al. 2016

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“…Therefore we decided to consider only the caustic technique with F β = 0.5 (the same value has been recently adopted by Geller et al 2013). Given that for r s < r < 4r s ≈ r 200 one can approximate F β cst typically to ±11% accuracy, the mass profile returned by the caustic method changes normalization but not the shape for different values of F β .…”

Section: Practical Implementationmentioning

confidence: 99%

Mass, velocity anisotropy, and pseudo phase-space density profiles of Abell 2142

Munari

Biviano

Mamon

2014

A&A

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Aims. We aim to compute the mass and velocity anisotropy profiles of Abell 2142 and, from there, the pseudo phase-space density profile Q(r) and the density slope − velocity anisotropy β − γ relation, and then to compare them with theoretical expectations. Methods. The mass profiles were obtained by using three techniques based on member galaxy kinematics, namely the caustic method, the method of dispersion-kurtosis, and MAMPOSSt. Through the inversion of the Jeans equation, it was possible to compute the velocity anisotropy profiles. Results. The mass profiles, as well as the virial values of mass and radius, computed with the different techniques agree with one another and with the estimates coming from X-ray and weak lensing studies. A combined mass profile is obtained by averaging the lensing, X-ray, and kinematics determinations. The cluster mass profile is well fitted by an NFW profile with c = 4.0 ± 0.5. The population of red and blue galaxies appear to have a different velocity anisotropy configuration, since red galaxies are almost isotropic, while blue galaxies are radially anisotropic, with a weak dependence on radius. The Q(r) profile for the red galaxy population agrees with the theoretical results found in cosmological simulations, suggesting that any bias, relative to the dark matter particles, in velocity dispersion of the red component is independent of radius. The β − γ relation for red galaxies matches the theoretical relation only in the inner region. The deviations might be due to the use of galaxies as tracers of the gravitational potential, unlike the non-collisional tracer used in the theoretical relation.

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“…Furthermore, and in contrast to the latter, caustics are not affected by the correlated large-scale structures along the line of sight (Diaferio 1999;Serra et al 2011;Geller et al 2013) because removing background/foreground at Δv > 3000 km s −1 is straightforward with spectroscopy that is needed anyway for caustics. This is magnificently illustrated by the cluster pair MS0906.5+1110/Abell 750: these clusters are offset by only 3000 km s −1 and are almost on the same line of sight.…”

Section: Introductionmentioning

confidence: 99%

Making the observational parsimonious richness a working mass proxy

Andreon

2015

A&A

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Richness, i.e., the number of bright cluster galaxies, is known to correlate with the cluster mass, however, to exploit it as mass proxy we need a way to estimate the aperture in which galaxies should be counted that minimizes the scatter between mass and richness. In this work, using a sample of 39 clusters with accurate caustic masses at 0.1 < z < 0.22, we first show that the scatter between mass and richness derived from survey data is negligibly small, as small as best mass proxies. The scatter turns out to be smaller than in some previous works and has a 90% upper limit of 0.05 dex in mass. The current sample, adjoining 76 additional clusters analyzed in previous works, establishes an almost scatterless, minimally evolving (if at all), mass-richness scaling in the redshift range 0.03 < z < 0.55. We then exploit this negligible scatter to derive the reference aperture to be used to compute richness and to predict the mass of cluster samples. These predicted masses have a total 0.16 dex scatter with caustic mass, about half of which is not intrinsic to the proxy, but related to the noisiness of the caustic masses used for test proxy performances. These results make richness-based masses of best quality and available for large samples at a low observational cost.

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Measuring the Mass Distribution in Galaxy Clusters

Cited by 67 publications

References 65 publications

Probing theories of gravity with phase space-inferred potentials of galaxy clusters

Probing theories of gravity with phase space-inferred potentials of galaxy clusters

Mass, velocity anisotropy, and pseudo phase-space density profiles of Abell 2142

Making the observational parsimonious richness a working mass proxy

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