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We study the properties of superclusters detected in the Abell/ACO cluster catalogue. We identify the superclusters utilizing the `friend-of-friend' procedure, and then determine supercluster shapes by using the differential geometry…

Astrophysics · Physics 2007-05-23 S. Basilakos , V. Kolokotronis , M. Plionis

We use catalogues of superclusters of galaxies from the 2dF Galaxy Redshift Survey to study the properties of galaxies in superclusters. We compare the properties of galaxies in high and low density regions of rich superclusters, in poor…

Differences in clustering properties between galaxy subpopulations complicate the cosmological interpretation of the galaxy power spectrum, but can also provide insights about the physics underlying galaxy formation. To study the nature of…

Astrophysics · Physics 2008-11-26 Molly E. C. Swanson , Max Tegmark , Michael Blanton , Idit Zehavi

We investigate the dynamical state of superclusters in Lambda cold dark matter ($\Lambda$CDM) cosmological models, where the density parameter $\Omega_0=0.2-0.4$ and $\sigma_8$ (the rms fluctuation on the $8h^{-1}$Mpc scale) is $0.7-0.9$.…

Astrophysics · Physics 2009-11-07 Mirt Gramann , Ivan Suhhonenko

Superclusters are a convenient way to partition and characterize the large scale structure of the Universe. In this Letter we explore the advantages of defining superclusters as watershed basins in the divergence velocity field. We apply…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-11 J. D. Peñaranda-Rivera , D. L Paipa-León , S. D. Hernández-Charpak , J. E. Forero-Romero

Two-dimensional high-resolution density field of galaxies of the Early Data Release of the Sloan Digital Sky Survey with a smoothing lengths 0.8 h^{-1} Mpc is applied to extract clusters of galaxies, and a low-resolution field with…

Astrophysics · Physics 2011-03-03 J. Einasto , G. H"utsi , M. Einasto , E. Saar , D. L. Tucker , V. M"uller , P. Hein"am"aki , S. S. Allam

We study the morphology of the richest superclusters from the catalogues of superclusters of galaxies in the 2dF Galaxy Redshift Survey and compare the morphology of real superclusters with model superclusters in the Millennium Simulation.…

Generally the dynamical state of superclusters is poorly known. We study properties of superclusters and select a sample of quasi-spherical superclusters, the dynamics of which can be studied using the $\Lambda$ significance diagram. We…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-07 Pekka Heinämäki , Pekka Teerikorpi , Marian Douspis , Pasi Nurmi , Maret Einasto , Mirt Gramann , Jukka Nevalainen , Enn Saar

In this paper, we consider clustering based on principal component analysis (PCA) for high-dimension, low-sample-size (HDLSS) data. We give theoretical reasons why PCA is effective for clustering HDLSS data. First, we derive a geometric…

Statistics Theory · Mathematics 2015-03-17 Kazuyoshi Yata , Makoto Aoshima

We investigate the evolution of superclusters and supercluster cocoons (basins of attraction), and the influence of cosmological parameters to the evolution. We perform numerical simulations of the evolution of the cosmic web for different…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-03 J. Einasto , G. Hütsi , I. Suhhonenko , L. J. Liivamägi , M. Einasto

The characterization of the internal structure of the superclusters of galaxies (walls, filaments and knots where the clusters are located) is paramount for understanding the formation of the Large Scale Structure and for outlining the…

Superclusters are the largest massive structures in the cosmic web on tens to hundreds of megaparsecs (Mpc) scales. They are the largest assembly of galaxy clusters in the Universe. Apart from a few detailed studies of such structures,…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-13 Shishir Sankhyayan , Joydeep Bagchi , Elmo Tempel , Surhud More , Maret Einasto , Pratik Dabhade , Somak Raychaudhury , Ramana Athreya , Pekka Heinämäki

We study the percolation of strongly connected clusters (SCCs), in which sites are mutually reachable through directed paths, in systems with randomly oriented bonds by extensive simulations on hypercubic lattices from dimension $d=2$ to…

Statistical Mechanics · Physics 2026-05-19 Qi Wang , Ming Li

We investigate the dependence of several galaxy properties on the environment and cluster identification techniques. We select clusters of galaxies from two catalogues based on the SDSS: the ROSAT-SDSS Galaxy Cluster Survey, and the MaxBCG…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 V. Coenda , H. Muriel

The description of complex configuration is a difficult issue. We present a powerful technique for cluster identification and characterization. The scheme is designed to treat with and analyze the experimental and/or simulation data from…

Statistical Mechanics · Physics 2013-08-29 Guangcai Zhang , Aiguo Xu , Guo Lu , Zeyao Mo

The discovery of the large-scale structure has transformed our view of galaxy formation and evolution. Filaments of the cosmic web provide key environments that channel the growth of structures. Guided by predictions from cosmological…

Astrophysics of Galaxies · Physics 2025-11-11 M. Mondelin , S. Codis , J-C. Cuillandre , C. Laigle , A. Boselli , K. Kraljic , C. Stone

We find clusters and superclusters of galaxies using the Data Release 1 of the Sloan Digital Sky Survey. We determine the luminosity function of clusters and find that clusters in a high-density environment have a luminosity a factor of ~5…

Astrophysics · Physics 2009-11-10 J. Einasto , E. Tago , M. Einasto , E. Saar , I. Suhhonenko , P. Hein"am"aki , G. Huetsi , D. L. Tucker

We measure the geometry, topology and morphology of the superclusters in mock SDSS catalogues prepared by Cole et al.(1998). The mock catalogues refer to $\tau$CDM and $\L$CDM {\em flat} cosmological models and are populated by galaxies so…

Astrophysics · Physics 2009-11-10 Jatush V. Sheth

This work is a continuation of the work of Kopylova and Kopylov (2016) to build a fundamental plane (FP) of groups and clusters of galaxies -- here a sample of galaxies systems is increased from 94 to 172 objects. We have studied the ratios…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-04 Flera G. Kopylova , Alexander I Kopylov

We extend the theoretical analysis of a recently proposed single subspace learning algorithm, called Dual Principal Component Pursuit (DPCP), to the case where the data are drawn from of a union of hyperplanes. To gain insight into the…

Computer Vision and Pattern Recognition · Computer Science 2019-07-19 Manolis C. Tsakiris , Rene Vidal