A Systematic Analysis of Caustic Methods for Galaxy Cluster Masses

Gifford, Daniel; Miller, Christopher J.; Kern, Nicholas S.

doi:10.1088/0004-637x/773/2/116

Cited by 77 publications

(90 citation statements)

References 54 publications

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“…We also find that if we under-populate the phase space, we can bias our low mass cluster potential profiles. This is a known effect and studied in detail in [29].…”

Section: B Desi Bright Galaxy Sample Forecastmentioning

confidence: 97%

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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 also find that if we under-populate the phase space, we can bias our low mass cluster potential profiles. This is a known effect and studied in detail in [29].…”

Section: B Desi Bright Galaxy Sample Forecastmentioning

confidence: 97%

“…the "phase space"). This is a well-developed and well-tested technique and it has been used in numerous studies of the mass profiles of galaxy clusters [29][30][31][32][33][34]. The escape edge for a given halo is constructed by taking the maximum velocity in the particle phase space for each r/R 200 bin in 0.05 intervals.…”

Section: Observablesmentioning

confidence: 99%

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

et al. 2016

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“…This occurs also when the best spectroscopic redshift datasets available are used and peculiar velocities are carefully considered when performing the assignments (for example, when the caustic method is used, Diaferio 1999;Gifford et al 2013;Yu et al 2015).…”

Section: Photometric Informationmentioning

confidence: 99%

A new method to assign galaxy cluster membership using photometric redshifts

Castignani

Benoist

2016

A&A

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We introduce a new effective strategy to assign group and cluster membership probabilities Pmem to galaxies using photometric redshift information. Large dynamical ranges both in halo mass and cosmic time are considered. The method takes into account the magnitude distribution of both cluster and field galaxies as well as the radial distribution of galaxies in clusters using a non-parametric formalism, and relies on Bayesian inference to take photometric redshift uncertainties into account. We successfully test the method against 1, 208 galaxy clusters within redshifts z = 0.05−2.58 and masses 10 13.29−14.80 M drawn from wide field simulated galaxy mock catalogs mainly developed for the forthcoming Euclid mission. Median purity and completeness values of (55 +17 −15 )% and (95 +5 −10 )% are reached for galaxies brighter than 0.25L * within r200 of each simulated halo and for a statistical photometric redshift accuracy σ((zs −zp)/(1+zs)) = 0.03.The mean values p = 56% and c = 93% are consistent with the median and have negligible sub-percent uncertainties. Accurate photometric redshifts (σ((zs − zp)/(1 + zs)) 0.05) and robust estimates for the cluster redshift and cluster center coordinates are required. The dependence of the assignments on photometric redshift accuracy, galaxy magnitude and distance from the halo center, and halo properties such as mass, richness, and redshift are investigated. Variations in the mean values of both purity and completeness are globally limited to a few percent. The largest departures from the mean values are found for galaxies associated with distant z 1.5 halos, faint (∼ 0.25 L * ) galaxies, and those at the outskirts of the halo (at cluster-centric projected distances ∼ r200) for which the purity is decreased, ∆p 20% at most, with respect to the mean value. The proposed method is applied to derive accurate richness estimates. A statistical comparison between the true (Ntrue) vs. estimated richness (λ = Pmem) yields on average to unbiased results, Log(λ/Ntrue) = −0.0051 ± 0.15. The scatter around the mean of the logarithmic difference between λ and the halo mass is 0.10 dex for massive halos 10 14.5 M . Our estimates could therefore be useful to constrain the cluster mass function and to calibrate independent cluster mass estimates such as those obtained from weak lensing, Sunyaev-Zel'dovich, and X-ray studies. Our method can be applied to any list of galaxy clusters or groups in both present and forthcoming surveys such as SDSS, CFHTLS, Pan-STARRS, DES, LSST, and Euclid.

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“…We follow the interloper removal prescriptions of Gifford et al (2013Gifford et al ( , 2016. The latter tested this edge-detection technique on projected data in two different simulations with widely varying values for s = 0.8…”

Section: Observablesmentioning

confidence: 99%

On Escaping a Galaxy Cluster in an Accelerating Universe

Stark

Miller

Gifford

2016

ApJ

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We derive the escape velocity profile for an Einasto density field in an accelerating universe and demonstrate its physical viability by comparing theoretical expectations to both light-cone data generated from N-body simulations and archival data on 20 galaxy clusters. We demonstrate that the projection function ( ( ) b g ) is deemed physically viable only for the theoretical expectation that includes a cosmology-dependent term. Using simulations, we show that the inferred velocity anisotropy is more than 6σ away from the expected value for the theoretical profile that ignores the acceleration of the universe. In the archival data, we constrain the average velocity anisotropy parameter of a sample of 20 clusters to be b = -+ 0.248 0.360 0.164 at the 68% confidence level. Lastly, we briefly discuss how our analytic model may be used as a novel cosmological probe based on galaxy clusters.

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A Systematic Analysis of Caustic Methods for Galaxy Cluster Masses

Cited by 77 publications

References 54 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

A new method to assign galaxy cluster membership using photometric redshifts

On Escaping a Galaxy Cluster in an Accelerating Universe

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