Investigating the Relation between Galaxy Properties and the Gaussianity of the Velocity Distribution of Groups and Clusters

Carvalho, R. R. de; Ribeiro, André; Stalder, D. H.; Rosa, Reinaldo R.; Costa, A P; Moura, T. C.

doi:10.3847/1538-3881/aa7f2b

Cited by 32 publications

(39 citation statements)

References 99 publications

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“…In Figure C1 in the appendix, we show the prevalence of highly substructured clusters as a function of log true mass, which we find increases for higher mass clusters. This trend is also identified in several observational studies which employ different dynamical substructure tests (e.g., Roberts & Parker 2017;de Carvalho et al 2017).…”

Section: Mock Cluster Sample and Analysismentioning

confidence: 81%

Galaxy Cluster Mass Reconstruction Project – III. The impact of dynamical substructure on cluster mass estimates

Old

Wojtak

Pearce

et al. 2017

Monthly Notices of the Royal Astronomical Society

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With the advent of wide-field cosmological surveys, we are approaching samples of hundreds of thousands of galaxy clusters. While such large numbers will help reduce statistical uncertainties, the control of systematics in cluster masses becomes ever more crucial. Here we examine the effects of an important source of systematic uncertainty in galaxy-based cluster mass estimation techniques: the presence of significant dynamical substructure. Dynamical substructure manifests as dynamically distinct subgroups in phase-space, indicating an unrelaxed state. This issue affects around a quarter of clusters in a generally selected sample. We employ a set of mock clusters whose masses have been measured homogeneously with commonly-used galaxy-based mass estimation techniques (kinematic, richness, caustic, radial methods). We use these to study how the relation between observationally estimated and true cluster mass depends on the presence of substructure, as identified by various popular diagnostics. We find that the scatter for an ensemble of clusters does not increase dramatically for clusters with dynamical substructure. However, we find a systematic bias for all methods, such that clusters with significant substructure have higher measured masses than their relaxed counterparts. This bias depends on cluster mass: the most massive clusters are largely unaffected by the presence of significant substructure, but masses are significantly overestimated for lower mass clusters, by ∼ 10% at 10 14 and 20% for 10 13.5 . The use of cluster samples with different levels of substructure can therefore bias certain cosmological parameters up to a level comparable to the typical uncertainties in current cosmological studies.

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Section: Mock Cluster Sample and Analysismentioning

confidence: 81%

Galaxy Cluster Mass Reconstruction Project – III. The impact of dynamical substructure on cluster mass estimates

Old

Wojtak

Pearce

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…Interestingly, the HDSGs that do not have evidence for star formation at their centers primarily occupy the small velocity, large radius region of the arc-like shape in PPS. The KDE contours reveal that the PASGs and SFGs exhibit a mirrorflipped distribution about the R/R 200 axis: the density of SFGs increases with radius and the velocity spread stays rel- We test the significance of the difference observed in the PPS distributions for the PASG, SFG, and HDSG samples using the multivariate two-sample KDE test developed by Duong et al (2012) for the purpose of comparing cell morphologies, and recently applied to PPS distributions by Lopes et al (2017) andde Carvalho et al (2017). The KDE test is nonparametric and uses the integrated square error as a measure of the discrepancy between two KDEs to test the hypothesis that two distributons are drawn from the same underlying density distribution (see Duong et al 2012, for details).…”

Section: Projected Phase Space Distributionmentioning

confidence: 99%

The SAMI Galaxy Survey: Quenching of Star Formation in Clusters I. Transition Galaxies

Owers

Hudson

Oman

et al. 2019

ApJ

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We use integral field spectroscopy from the SAMI Galaxy Survey to identify galaxies that show evidence for recent quenching of star formation. The galaxies exhibit strong Balmer absorption in the absence of ongoing star formation in more than 10% of their spectra within the SAMI field of view. These Hδ-strong galaxies (HDSGs) are rare, making up only ∼ 2% (25/1220) of galaxies with stellar mass log(M * /M ⊙ )> 10. The HDSGs make up a significant fraction of non-passive cluster galaxies (15%; 17/115) and a smaller fraction (2.0%; 8/387) of the non-passive population in low-density environments. The majority (9/17) of cluster HDSGs show evidence for star formation at their centers, with the HDS regions found in the outer parts of the galaxy. Conversely, the Hδ-strong signal is more evenly spread across the galaxy for the majority (6/8) of HDSGs in low-density environments, and is often associated with emission lines that are not due to star formation. We investigate the location of the HDSGs in the clusters, finding that they are exclusively within 0.6R 200 of the cluster centre, and have a significantly higher velocity dispersion relative to the cluster population. Comparing their distribution in projected-phase-space to those derived from cosmological simulations indicates that the cluster HDSGs are consistent with an infalling population that have entered the central 0.5r 200,3D cluster region within the last ∼ 1 Gyr. In the 8/9 cluster HDSGs with central star formation, the extent of star formation is consistent with that expected of outside-in quenching by ram-pressure stripping. Our results indicate that the cluster HDSGs are currently being quenched by ram-pressure stripping on their first passage through the cluster.

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“…In any case, there are increasingly more observations and simulations that appear to occasionally contradict, where many authors suggests a need for pre-processing (Haines et al 2015;Roberts & Parker 2017;de Carvalho et al 2017). Mulroy et al (2017) argues for a bi-modality on infall and accretion histories with similar accretion rates, one with pre-processing and one without, in order to explain the variations in colour found in non-merging systems.…”

Section: Interpreting the Vdpsmentioning

confidence: 99%

The kinematics of cluster galaxies via velocity dispersion profiles

Bilton

Pimbblet

2018

Monthly Notices of the Royal Astronomical Society

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We present an analysis of the kinematics of a sample of 14 galaxy clusters via velocity dispersion profiles (VDPs), compiled using cluster parameters defined within the X-Ray Galaxy Clusters Database (BAX) cross-matched with data from the Sloan Digital Sky Survey (SDSS). We determine the presence of substructure in the clusters from the sample as a proxy for recent core mergers, resulting in 4 merging and 10 nonmerging clusters to allow for comparison between their respective dynamical states. We create VDPs for our samples and divide them by mass, colour and morphology to assess how their kinematics respond to the environment. To improve the signalto-noise ratio our galaxy clusters are normalised and co-added to a projected cluster radius at 0.0 − 2.5 r 200 . We find merging cluster environments possess an abundance of a kinematically-active (rising VDP) mix of red and blue elliptical galaxies, which is indicative of infalling substructures responsible for pre-processing galaxies. Comparatively, in non-merging cluster environments galaxies generally decline in kinematic activity as a function of increasing radius, with bluer galaxies possessing the highest velocities, likely as a result of fast infalling field galaxies. However, the variance in kinematic activity between blue and red cluster galaxies across merging and non-merging cluster environments suggests galaxies exhibit differing modes of galaxy accretion onto a cluster potential as a function of the presence of a core merger.

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Investigating the Relation between Galaxy Properties and the Gaussianity of the Velocity Distribution of Groups and Clusters

Cited by 32 publications

References 99 publications

Galaxy Cluster Mass Reconstruction Project – III. The impact of dynamical substructure on cluster mass estimates

Galaxy Cluster Mass Reconstruction Project – III. The impact of dynamical substructure on cluster mass estimates

The SAMI Galaxy Survey: Quenching of Star Formation in Clusters I. Transition Galaxies

The kinematics of cluster galaxies via velocity dispersion profiles

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