Clusters and groups of galaxies in the 2dF galaxy redshift survey: A new catalogue

Abstract

We create a new catalogue of groups and clusters, applying the friends-of-friends method to the 2dF GRS final release. We investigate various selection effects due to the use of a magnitude limited sample. For this purpose we follow the changes in group sizes and mean galaxy number densities within groups when shifting nearby observed groups to larger distances. We study the distribution of sizes of dark matter haloes in N -body simulations and compare properties of these haloes and the 2dF groups. We show that at large distances from the observer luminous and intrinsically greater groups dominate, but in these groups only very bright members are seen, which form compact cores of the groups. These two effects almost cancel each other, so that the mean sizes and densities of groups do not change considerably with distance. Our final sample contains 10750 groups in the Northern part, and 14465 groups in the Southern part of the 2dF survey with membership N gal ≥ 2. We estimate the total luminosities of our groups, correcting for group members fainter than the observational limit of the survey. The cluster catalogue is available at our web-site

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

“…Today, many extensive FoF group and cluster catalogues are available, varying in the sample data and details of the group-finder algorithm (e.g. Tucker et al 2000;Eke et al 2004;Tago et al 2006Tago et al , 2008.…”

Groups and clusters of galaxies in the SDSS DR8

“…During the last decade, several group catalogues that use spectroscopic redshifts have been published, either based on the 2dFGRS (Eke et al 2004;Yang et al 2005;Tago et al 2006), or on earlier releases of the SDSS (Einasto et al 2003;Merchán & Zandivarez 2005;Zandivarez et al 2006;Berlind et al 2006;Berlind & SDSS 2009;Yang et al 2007;Koester et al 2007). However, similar algorithms used to compile these catalogues have yielded groups of galaxies with rather different statistical properties.…”

Groups of galaxies in the SDSS Data Release 7

“…The next generation of galaxy group catalogues started from the Las Campanas catalogue of groups by Tucker et al (2000) and was followed by the catalogues based on the 2 degree Field Galaxy Redshift Survey (2dFGRS) data releases (Colless et al 2001(Colless et al , 2003 and the Sloan Digital Sky Survey (SDSS) data releases (Early Data Release, Data Release 1-Data Release 7) (Adelman-McCarthy et al 2008). As one of several important results more search algorithms were developed (De Propris et al 2002;Goto et al 2002;Merchán & Zandivarez 2002;Bahcall et al 2003;Lee et al 2004;Eke et al 2004;Merchán & Zandivarez 2005;Yang et al 2005;Einasto et al 2005;Weinmann et al 2006; Full Table 2 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/514/A102 Tago et al 2006;Berlind et al 2006;Deng et al 2007;Yang et al 2007;Tago et al 2008).…”

“…In our previous papers (Tago et al 2006(Tago et al , 2008, hereafter Papers I and II) we extracted 2dFGRS and SDSS DR5 groups as flux-limited samples. In those papers we gave an extensive review of previous studies dedicated to group search methods, and of the published group catalogues.…”

“…In recent years, several authors have compiled group catalogues using the 2dFGRS (Eke et al 2004;Yang et al 2005;Tago et al 2006). Using earlier releases of the SDSS, preliminary catalogues of groups have been obtained (Einasto et al 2003a; Lee et al 2004;Merchán & Zandivarez 2005;Goto 2005;Yang et al 2005;Weinmann et al 2006;Zandivarez et al 2006;Berlind et al 2006;Yang et al 2007).…”