Clusters and superclusters in the Sloan Digital Sky Survey

¹ Tartu Observatory, 61602 Tõravere, Estonia
² Fermi National Accelerator Laboratory, MS 127, PO Box 500, Batavia, IL 60510, USA
³ Astrophysical Institute Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
⁴ Tuorla Observatory, Väisäläntie 20, Piikkiö, Finland
⁵ National Research Institute for Astronomy & Geophysics, Helwan Observatory, Cairo, Egypt

Corresponding author: J. Einasto, einasto@aai.ee

Received: 9 December 2002
Accepted: 13 March 2003

Abstract

We apply the 2-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 to extract clusters and groups of galaxies, and a low-resolution field with smoothing lengths 10 h^-1 Mpc to extract superclusters of galaxies. We investigate properties of density field clusters and superclusters and compare properties of these clusters and superclusters with Abell clusters, and superclusters found on the basis of Abell clusters. We found that clusters in high-density environment have a luminosity a factor of higher than in low-density environment. There exists a large anisotropy between the SDSS Northern and Southern sample in the properties of clusters and superclusters: most luminous clusters and superclusters in the Northern sample are a factor of 2 more luminous than the respective systems in the Southern sample.