The luminosity, colour and morphology dependence of galaxy filaments in the Sloan Digital Sky Survey Data Release Four

Pandey, Biswajit; Bharadwaj, Somnath

doi:10.1111/j.1365-2966.2006.10894.x

Cited by 46 publications

(55 citation statements)

References 102 publications

(110 reference statements)

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“…The Universe's main matter (dark matter) follows a hierarchical model of structure formation and evolution (Kaiser 1986;White & Frenk 1991) depicted in great detail with numerical simulations, which trace the gravitational growth of dark matter haloes (Evrard et al 2002;Springel et al 2005;Dolag et al 2006). The so-called cosmic web filling the present Universe has been observationally confirmed by several large spectroscopic surveys (Colless et al 2001;Pimbblet et al 2004;Pandey & Bharadwaj 2006), revealing the presence of large-scale filaments that feed nodes of massive and rich galaxy clusters (e.g. Jauzac et al 2012).…”

Section: Introductionmentioning

confidence: 88%

SARCS strong-lensing galaxy groups

Foëx¹,

Motta²,

Limousin³

et al. 2013

A&A

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We present the weak-lensing and optical analysis of the SL2S-ARCS (SARCS) sample of strong-lensing candidates. The sample is based on the Strong Lensing Legacy Survey (SL2S), a systematic search of strong-lensing systems in the photometric CanadaFrance-Hawaii Telescope Legacy Survey (CFHTLS). The SARCS sample focusses on arc-like features and is designed to contain mostly galaxy groups. We briefly present the weak-lensing methodology that we used to estimate the mass of the SARCS objects. Among 126 candidates, we obtained a weak-lensing detection (at the 1σ level) for 89 objects with velocity dispersions of the singular isothermal sphere mass model (SIS) ranging from σ SIS ∼ 350 km s −1 to ∼1000 km s −1 with an average value of σ SIS ∼ 600 km s −1 , corresponding to a rich galaxy group (or poor cluster). From the galaxies belonging to the bright end of the group's red sequence (M i < −21), we derived the optical properties of the SARCS candidates. We obtained typical richnesses of N ∼ 5−15 galaxies and optical luminosities of L ∼ 0.5−1.5 × 10 12 L (within a radius of 0.5 Mpc). We used these galaxies to compute luminosity density maps, from which a morphological classification reveals that a large fraction of the sample (∼45%) are groups with a complex light distribution, either elliptical or multi-modal, suggesting that these objects are dynamically young structures. We finally combined the lensing and optical analyses to define a sample of the 80 most secure group candidates, i.e. weak-lensing detection and over-density at the lens position in the luminosity map, to remove false detections and galaxy-scale systems from the initial sample. We use this reduced sample to probe the optical scaling relations in combination with a sample of massive galaxy clusters. We detect the expected correlations over the probed range in mass with a typical scatter of ∼25% in σ SIS at a given richness or luminosity, making these scaling laws interesting mass proxies.

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Section: Introductionmentioning

confidence: 88%

SARCS strong-lensing galaxy groups

Foëx¹,

Motta²,

Limousin³

et al. 2013

A&A

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“…Systems of galaxies determined in the SDSS have been studied by a number of authors (Pandey & Bharadwaj 2005;Gott et al 2005;Park et al 2005;Pandey & Bharadwaj 2006;Gott et al 2008;Pandey & Bharadwaj 2008;Kitaura et al 2009;Choi et al 2010;Sousbie et al 2011;Einasto et al 2011b,a;Sheth & Diaferio 2011;Pimbblet et al 2011;Platen et al 2011). The overall shapes of superclusters have been described by the shape parameters or approximated by triaxial ellipses (Jaaniste et al 1998;Basilakos et al 2001;Kolokotronis et al 2002;Basilakos 2003;Einasto et al 2007aEinasto et al , 2011bCosta-Duarte et al 2011;Luparello et al 2011).…”

Section: Discussionmentioning

confidence: 99%

SDSS DR7 superclusters

Einasto

Liivamägi

Saar

et al. 2011

A&A

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Context. The study of superclusters of galaxies helps us to understand the formation, evolution, and present-day properties of the large-scale structure of the Universe. Aims. We use data about superclusters drawn from the SDSS DR7 to analyse possible selection effects in the supercluster catalogue, to study the physical and morphological properties of superclusters, to find their possible subsets, and to determine scaling relations for our superclusters. Methods. We apply principal component analysis and Spearman's correlation test to study the properties of superclusters. Results. We have found that the parameters of superclusters do not correlate with their distance. The correlations between the physical and morphological properties of superclusters are strong. Superclusters can be divided into two populations according to their total luminosity: high-luminosity ones with L g > 400 × 10 10 h −2 L and low-luminosity systems. High-luminosity superclusters form two sets, which are more elongated systems with the shape parameter K 1 /K 2 < 0.5 and less elongated ones with K 1 /K 2 > 0.5. The first two principal components account for more than 90% of the variance in the supercluster parameters. We use principal component analysis to derive scaling relations for superclusters, in which we combine the physical and morphological parameters of superclusters. Conclusions. The first two principal components define the fundamental plane, which characterises the physical and morphological properties of superclusters. Structure formation simulations for different cosmologies, and more data about the local and high redshift superclusters are needed to understand the evolution and the properties of superclusters better.

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“…Trujillo et al (2006) also showed by analyzing recent observational data from large galaxy surveys that the spin axes of void galaxies tend to be inclined to the void surfaces, retaining an initial memory of tidally induced alignment. Pandey & Bharadwaj (2006) have shown that galaxy luminosity and color depend on the filamentarity of the large-scale environment. More recently, they also presented the result that the star formation rates of galaxies are correlated with the filamentarity of the surrounding large-scale structure (Pandey & Bharadwaj 2008).…”

Section: Introductionmentioning

confidence: 99%

“…Pandey & Bharadwaj (2006) have shown that galaxy luminosity and color depend on the filamentarity of the large-scale environment. More recently, they also presented the result that the star formation rates of galaxies are correlated with the filamentarity of the surrounding large-scale structure (Pandey & Bharadwaj 2008). Hernandez et al (2007) found a one-to-one correspondence between the value of the galaxy spin parameter and morphological type, while Hernandez & Cervantes-Sodi (2006) and Cervantes-Sodi & Hernandez (2008) have noted that the spin parameters of observed galaxies are strongly correlated with their color and chemical abundance.…”

Section: Introductionmentioning

confidence: 99%

The Variation of Galaxy Morphological Type with Environmental Shear

Lee

2008

Astrophysical Journal

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Recent N-body simulations indicate that the assembly history of galactic halos depends on the density of the largescale environment. This implies that galaxy properties such as age and size of the bulge may also vary with the surrounding large-scale structures, which are characterized by tidal shear as well as density. Using a sample of 15,882 well-resolved nearby galaxies from the Tully catalog and the real-space tidal field reconstructed from the 2MASS Redshift Survey, we investigate the dependence of galaxy morphological type on the shear of the large-scale environment in which they are embedded. We first calculate the large-scale dimensionless overdensities () and ellipticities (e) of the regions where the galaxies are located, classify them according to morphological type, and create subsamples selected at similar -values but spanning different ranges in e. We calculate the mean ellipticity, hei, averaged over each subsample and find a signal of variation of hei with morphological type: for 0.5 1.0, elliptical galaxies are preferentially located in regions with low ellipticity; for À0.3 0.1, the latest-type spirals are preferentially located in regions with high ellipticity. The null hypothesis that the mean ellipticities of the regions where the ellipticals and the latest-type spirals are located are the same as the global mean ellipticity averaged over all types is rejected at the 3 level when À0.3 0.1. Yet, no signal of a galaxy-shear correlation is found in highly overdense or underdense regions. The observed trend suggests that the formation epochs of galactic halos might be a function of not only halo mass and large-scale density but also large-scale shear. Since the statistical significance of the overall trend is low, a sample of at least 100,000 galaxies is required to verify this correlation. Subject headingg s: cosmology: observations -large-scale structure of universe

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The luminosity, colour and morphology dependence of galaxy filaments in the Sloan Digital Sky Survey Data Release Four

Cited by 46 publications

References 102 publications

SARCS strong-lensing galaxy groups

SARCS strong-lensing galaxy groups

SDSS DR7 superclusters

The Variation of Galaxy Morphological Type with Environmental Shear

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