Non-Gaussian velocity distributions — the effect on virial mass estimates of galaxy groups

Ribeiro, André; Lopes, P. A. A.; Trevisan, M.

doi:10.1111/j.1745-3933.2011.01038.x

Cited by 33 publications

(51 citation statements)

References 22 publications

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“…They probably even correspond to the main cause of non-normality in the velocity distribution in clusters (e.g. Ribeiro et al 2011;Hou et al 2012;Einasto et al 2012a,b;Krause et al 2013). Therefore, the dip method helps us to better estimate which the intrinsically Gaussian velocity distributed clusters are and which are not.…”

Section: Gaussian and Non-gaussian Composite Clustersmentioning

confidence: 99%

“…Hence, distinguishing galaxy clusters according to their velocity distributions may be an objective way to assess their dynamics through the simple use of statistical tests (see e.g. Hou et al 2009;Ribeiro et al 2010Ribeiro et al , 2011.…”

Section: Gaussian and Non-gaussian Composite Clustersmentioning

confidence: 99%

“…The velocity dispersions of the composite clusters, σ u , refer to the dimensionless quantity u i (see Ribeiro et al 2010Ribeiro et al , 2011. The virial properties of non-Gaussian clusters were corrected after an iteratively removing galaxies without which the clusters are Gaussian.…”

Section: Gaussian and Non-gaussian Composite Clustersmentioning

confidence: 99%

“…The virial properties of non-Gaussian clusters were corrected after an iteratively removing galaxies without which the clusters are Gaussian. On average, 15% of the galaxies in non-Gaussian clusters need to be removed in this process.The corrected properties are just those the cluster would have if it consisted only of galaxies consistent with the normal velocity distribution (see Perea et al 1990;Ribeiro et al 2011). This correction allows one to approximately compare virial properties of Gaussian and nonGaussian clusters.…”

Section: Gaussian and Non-gaussian Composite Clustersmentioning

confidence: 99%

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NoSOCS in SDSS

Ribeiro

Lopes

Rembold

2013

A&A

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Context. We investigate relations between the color and luminosity distributions of cluster galaxies and the evolutionary state of their host clusters. Aims. Our aim is to explore some aspects of cluster galaxy evolution and the dynamical state of clusters as two sides of the same process. Methods. We used 10 721 member galaxies of 183 clusters extracted from the Sloan Digital Sky Survey using a list of NoSOCS and CIRS targets. First, we classified the clusters into two categories, Gaussian and non-Gaussian, according to their velocity distribution measurements, which we used as an indicator of their dynamical state. We then used objective criteria to split up galaxies according to their luminosities, colors, and photometric mean stellar age. This information was then used to evaluate how galaxies evolve in their host clusters. Results. Meaningful color gradients, i.e., the fraction of red galaxies as a function of radius from the center, are observed for both the Gaussian velocity distribution and the non-Gaussian velocity distribution cluster subsamples, which suggests that member galaxy colors change on a shorter timescale than the time needed for the cluster to reach dynamical equilibrium. We also found that larger portions of fainter red galaxies are found, on average, in smaller radii. The luminosity function in Gaussian clusters has a brighter characteristic absolute magnitude and a steeper faint-end slope than it does in the non-Gaussian velocity distribution clusters. Conclusions. Our findings suggest that cluster galaxies experience intense color evolution before virialization, while the formation of faint galaxies through dynamical interactions probably takes place on a longer timescale, possibly longer than the virialization time.

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Section: Gaussian and Non-gaussian Composite Clustersmentioning

confidence: 99%

Section: Gaussian and Non-gaussian Composite Clustersmentioning

confidence: 99%

Section: Gaussian and Non-gaussian Composite Clustersmentioning

confidence: 99%

Section: Gaussian and Non-gaussian Composite Clustersmentioning

confidence: 99%

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NoSOCS in SDSS

Ribeiro

Lopes

Rembold

2013

A&A

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“…Yahil & Vidal 1977), while in peripheral areas they can show deviations from Gaussianity (e.g. Ribeiro, Lopes & Trevisan 2011). This indicates that the central parts are probably in dynamical equilibrium, when outskirts continue to accumulate matter from the surroundings.…”

Section: Introductionmentioning

confidence: 99%

Dynamical analysis of the cluster pair: A3407 + A3408

Nascimento

Ribeiro

Trevisan

et al. 2016

Mon. Not. R. Astron. Soc.

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We carried out a dynamical study of the galaxy cluster pair A3407 & A3408 based on a spectroscopic survey obtained with the 4 meter Blanco telescope at the CTIO, plus 6dF data, and ROSAT All-Sky-Survey. The sample consists of 122 member galaxies brighter than m R = 20. Our main goal is to probe the galaxy dynamics in this field and verify if the sample constitutes a single galaxy system or corresponds to an ongoing merging process. Statistical tests were applied to clusters members showing that both the composite system A3407 + A3408 as well as each individual cluster have Gaussian velocity distribution. A velocity gradient of ∼ 847 ± 114 km s −1 was identified around the principal axis of the projected distribution of galaxies, indicating that the global field may be rotating. Applying the KMM algorithm to the distribution of galaxies we found that the solution with two clusters is better than the single unit solution at the 99% c.l. This is consistent with the X-ray distribution around this field, which shows no common X-ray halo involving A3407 and A3408. We also estimated virial masses and applied a two-body model to probe the dynamics of the pair. The more likely scenario is that in which the pair is gravitationally bound and probably experiences a collapse phase, with the cluster cores crossing in less than ∼1 h −1 Gyr, a pre-merger scenario. The complex X-ray morphology, the gas temperature, and some signs of galaxy evolution in A3408 suggests a post-merger scenario, with cores having crossed each other ∼ 1.65h −1 Gyr ago, as an alternative solution.

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The Galaxy Cluster Mass Scale and Its Impact on Cosmological Constraints from the Cluster Population

et al. 2019

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The total mass of a galaxy cluster is one of its most fundamental properties. Together with the redshift, the mass links observation and theory, allowing us to use the cluster population to test models of structure formation and to constrain cosmological parameters. Building on the rich heritage from X-ray surveys, new results from Sunyaev-Zeldovich and optical surveys have stimulated a resurgence of interest in cluster cosmology. These studies have generally found fewer clusters than predicted by the baseline Planck ΛCDM model, prompting a renewed effort on the part of the commu-nity to obtain a definitive measure of the true cluster mass scale. Here we review recent progress on this front. Our theoretical understanding continues to advance, with numerical simulations being the cornerstone of this effort. On the observational side, new, sophisticated techniques are being deployed in individual mass measurements and to account for selection biases in cluster surveys. We summarise the state of the art in cluster mass estimation methods and the systematic uncertainties and biases inherent in each approach, which are now well identified and understood, and explore how current uncertainties propagate into the cosmological parameter analysis. We discuss the prospects for improvements to the measurement of the mass scale using upcoming multiwavelength data, and the future use of the cluster population as a cosmological probe.

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Non-Gaussian velocity distributions — the effect on virial mass estimates of galaxy groups

Cited by 33 publications

References 22 publications

NoSOCS in SDSS

NoSOCS in SDSS

Dynamical analysis of the cluster pair: A3407 + A3408

The Galaxy Cluster Mass Scale and Its Impact on Cosmological Constraints from the Cluster Population

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