Toward understanding environmental effects in SDSS clusters

Einasto, J.; Tago, E.; Einasto, M.; Saar, E.; Suhhonenko, I.; Heinämäki, P.; Hütsi, Gert; Tucker, D. L.

doi:10.1051/0004-6361:20042347

Cited by 29 publications

(44 citation statements)

References 67 publications

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“…More massive galaxies also acquire galactic structures like bars earlier, showing that dynamical maturity of disks also follows cosmic downsizing (Sheth et al 2008). Finally, Einasto et al (2005) claim that clusters in high density regions evolve more rapidly than in low density environments, supporting the theoretical expectation of an acceleration of structure formation in denser environments.…”

Section: Role Of the Environment On Galaxy Formation And Evolutionsupporting

confidence: 51%

The zCOSMOS redshift survey: the role of environment and stellar mass in shaping the rise of the morphology-density relation from z ~ 1

Tasca

Kneib²,

Iovino

et al. 2009

A&A

152

146

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Context. For more than two decades we have known that galaxy morphological segregation is present in the Local Universe. It is important to see how this relation evolves with cosmic time. Aims. To investigate how galaxy assembly took place with cosmic time, we explore the evolution of the morphology-density relation up to redshift z ∼ 1 using about 10 000 galaxies drawn from the zCOSMOS Galaxy Redshift Survey. Taking advantage of accurate HST/ACS morphologies from the COSMOS survey, of the well-characterised zCOSMOS 3D environment, and of a large sample of galaxies with spectroscopic redshift, we want to study here the evolution of the morphology-density relation up to z ∼ 1 and its dependence on galaxy luminosity and stellar mass. The multi-wavelength coverage of the field also allows a first study of the galaxy morphological segregation dependence on colour. We further attempt to disentangle between processes that occurred early in the history of the Universe or late in the life of galaxies. Methods. The zCOSMOS field benefits of high-resolution imaging in the F814W filter from the Advanced Camera for Survey (ACS). We use standard morphology classifiers, optimised for being robust against band-shifting and surface brightness dimming, and a new, objective, and automated method to convert morphological parameters into early, spiral, and irregular types. We use about 10 000 galaxies down to I AB = 22.5 with a spectroscopic sampling rate of 33% to characterise the environment of galaxies up to z ∼ 1 from the 100 kpc scales of galaxy groups up to the 100 Mpc scales of the cosmic web. The evolution of the morphology-density relation in different environments is then studied for luminosity and stellar-mass selected, volume-limited samples of galaxies. The trends are described and related to the various physical processes that could play a relevant role in the build-up of the morphology-density relation. Results. We confirm that the morphological segregation is present up to z ∼ 1 for luminosity-selected, volume-limited samples. The behaviour of the morphology-density relation gets flatter at fixed masses expecially above 10 10.6 M . We suggest the existence of a critical mass above which the physical processes governing galaxy stellar mass also determine the shaping of the galaxy more than its environment. We finally show that at a fixed morphology there is still a residual variation in galaxy colours with density. Conclusions. The observed evolution with redshift of the morphology-density relation offers an opportunity to trace the effect of nature and nurture as a function of environment. Even though it is based mainly on a biased view, the environmental dependence of the morphological evolution for luminosity-selected, volume-limited samples seems to indicate that nurture is in play. On the other hand, the lack of evolution observed for earlytype and spiral galaxies that are more massive than 10 10.8 M independents of the environment indicates that nature has imprinted these properties early in the life of...

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Section: Role Of the Environment On Galaxy Formation And Evolutionsupporting

confidence: 51%

The zCOSMOS redshift survey: the role of environment and stellar mass in shaping the rise of the morphology-density relation from z ~ 1

Tasca

Kneib²,

Iovino

et al. 2009

A&A

152

146

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“…Finally, for supercluster scales, numerical simulations by Einasto et al (2005) showed that in voids the dynamical evolution of halos is very slow and finally stops, while in supercluster regions the dynamical evolution continues until the present day. In superclusters, rich clusters at the core regions form first via halo mergers.…”

Section: Discussionmentioning

confidence: 96%

“…The core regions of rich superclusters contain a higher fraction of early-type, red galaxies and richer groups than the outskirts of superclusters . Galaxy clusters in high-density environments are about 5 times more luminous than in low-density environments (Einasto et al 2005).…”

Section: Superclusters and Quasarsmentioning

confidence: 97%

Environments of nearby quasars in Sloan Digital Sky Survey

Lietzen

Heinämäki

Nurmi

et al. 2009

A&A

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Context. For the first time, spectroscopic galaxy redshift surveys are enabling galaxies to be studied with the nearest quasars. This allows the dependence of the activity of a quasar on its environment to be studied in a more extensive way than before. Aims. We study the spatial distribution of galaxies and properties of groups of galaxies in the environments of low redshift quasars in the Sloan Digital Sky Survey (SDSS). Our aim is to understand how the nearby quasars are embedded in the local and global density field of galaxies and how the environment affects quasar activity. Methods. We analyze the environments of nearby quasars using number counts of galaxies. We also study the dependence of group properties on their distance to the nearest quasar. The large-scale environments are studied by analyzing the locations of quasars in the luminosity density field. Results. Our study of the number counts of galaxies in quasar environments shows an underdensity of bright galaxies at a few Mpc from quasars. Groups of galaxies with a quasar closer than 2 Mpc are also poorer and less luminous than average. Our analysis of the luminosity density field shows that quasars clearly avoid rich superclusters. Nearby quasars seem to be located in the outskirts of superclusters or in the filaments connecting them. Conclusions. Our results suggest that quasar evolution may be affected by density variations both on supercluster scales and in the local environment.

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“…Based on 3-dimensional data catalogues of superclusters were compiled on the basis of these new surveys by Basilakos (2003), Erdogdu et al (2004) and Porter & Raychaudhury (2005). These observational studies have been complemented by the analysis of the evolution of superclusters and the supercluster-void network (Shandarin et al 2004;Einasto et al 2005b;Wray et al 2006).…”

Section: Introductionmentioning

confidence: 99%

“…In an accompanying paper we shall investigate properties of superclusters and compare properties of real superclusters with those of simulated superclusters (Einasto et al 2007, hereafter Paper II). An analysis of the luminosity function of superclusters using both 2dFGRS and SDSS superclusters is presented by Einasto et al (2006a).…”

Section: Introductionmentioning

confidence: 99%

Superclusters of galaxies from the 2dF redshift survey

Einasto¹,

Einasto²,

Tago³

et al. 2006

A&A

Self Cite

120

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Aims. We use the 2dF Galaxy Redshift Survey data to compile catalogues of superclusters for the Northern and Southern regions of the 2dFGRS, altogether 543 superclusters at redshifts 0.009 ≤ z ≤ 0.2. Methods. We analyse methods of compiling supercluster catalogues and use results of the Millennium Simulation to investigate possible selection effects and errors. We find that the most effective method is the density field method using smoothing with an Epanechnikov kernel of radius 8 h −1 Mpc. Results. We derive positions of the highest luminosity density peaks and find the most luminous cluster in the vicinity of the peak, this cluster is considered as the main cluster and its brightest galaxy the main galaxy of the supercluster. In catalogues we give equatorial coordinates and distances of superclusters as determined by positions of their main clusters. We also calculate the expected total luminosities of the superclusters.

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Toward understanding environmental effects in SDSS clusters

Cited by 29 publications

References 67 publications

The zCOSMOS redshift survey: the role of environment and stellar mass in shaping the rise of the morphology-density relation from z ~ 1

The zCOSMOS redshift survey: the role of environment and stellar mass in shaping the rise of the morphology-density relation from z ~ 1

Environments of nearby quasars in Sloan Digital Sky Survey

Superclusters of galaxies from the 2dF redshift survey

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