Distribution and evolution of galaxy groups in the Ursa Major supercluster

Krause, Marcelo Rodrigo; Ribeiro, André; Lopes, P. A. A.

doi:10.1051/0004-6361/201220071

Cited by 14 publications

(18 citation statements)

References 30 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: 98%

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: 98%

NoSOCS in SDSS

Ribeiro

Lopes

Rembold

2013

A&A

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“…Regarding substructure we classify the clusters using the ∆ (or DS) test (Dressler & Shectman 1988) and the Hellinger Distance (HD) measure, used to detect deviations from a Gaussian velocity distribution (Ribeiro et al 2013b). In previous works (Krause, Ribeiro & Lopes 2013;Ribeiro et al 2013a) we considered different tests (such as Anderson-Darling and Kolmogorov-Smirnov) of gaussianity applied to the galaxy velocity distribution. For the current work we decided to adopt the HD measure as it is the least vulnerable method to type I and II statistical errors (Ribeiro et al 2013b).…”

Section: Role Of the Cluster Dynamical Stagementioning

confidence: 99%

NoSOCS in SDSS – VI. The environmental dependence of AGN in clusters and field in the local Universe

Lopes

Ribeiro

Rembold

2017

Monthly Notices of the Royal Astronomical Society

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We investigated the variation in the fraction of optical active galactic nuclei (AGN) hosts with stellar mass, as well as their local and global environments. Our sample is composed of cluster members and field galaxies at z ≤ 0.1 and we consider only strong AGN. We find a strong variation in the AGN fraction (F AGN ) with stellar mass. The field population comprises a higher AGN fraction compared to the global cluster population, especially for objects with log M * > 10.6. Hence, we restricted our analysis to more massive objects. We detected a smooth variation in the F AGN with local stellar mass density for cluster objects, reaching a plateau in the field environment. As a function of clustercentric distance we verify that F AGN is roughly constant for R > R 200 , but show a steep decline inwards. We have also verified the dependence of the AGN population on cluster velocity dispersion, finding a constant behavior for low mass systems (σ P 650 − 700 km s −1 ). However, there is a strong decline in F AGN for higher mass clusters (> 700 km s −1 ). When comparing the F AGN in clusters with or without substructure we only find different results for objects at large radii (R > R 200 ), in the sense that clusters with substructure present some excess in the AGN fraction. Finally, we have found that the phase-space distribution of AGN cluster members is significantly different than other populations. Due to the environmental dependence of F AGN and their phase-space distribution we interpret AGN to be the result of galaxy interactions, favored in environments where the relative velocities are low, typical of the field, low mass groups or cluster outskirts.

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“…Furthermore, the properties of groups in superclusters, and galaxies in them, can be studied (Einasto et al 2003(Einasto et al , 2011(Einasto et al , 2012Lietzen et al 2012;Krause et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Flux- and volume-limited groups/clusters for the SDSS galaxies: catalogues and mass estimation

Tempel

Tamm

Gramann

et al. 2014

A&A

230

488

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We provide flux-and volume-limited galaxy group and cluster catalogues based on the spectroscopic sample of the galaxies of SDSS data release 10. We used a modified friends-of-friends method with a variable linking length in the transverse and radial directions to identify as many realistic groups as possible. The flux-limited catalogue incorporates galaxies down to m r = 17.77 mag. It includes 588 193 galaxies and 82 458 groups. The volume-limited catalogues are complete for absolute magnitudes down to M r,lim = −18.0, −18.5, −19.0, −19.5, −20.0, −20.5, and −21.0; the completeness is achieved within different spatial volumes. Our analysis shows that flux-and volume-limited group samples are well compatible, especially for the larger groups/clusters. Dynamical mass estimates based on radial velocity dispersions and group extent in the sky were added to the extracted groups.

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Distribution and evolution of galaxy groups in the Ursa Major supercluster

Cited by 14 publications

References 30 publications

NoSOCS in SDSS

NoSOCS in SDSS

NoSOCS in SDSS – VI. The environmental dependence of AGN in clusters and field in the local Universe

Flux- and volume-limited groups/clusters for the SDSS galaxies: catalogues and mass estimation

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