Open AccessGalaxy groups in the 2dFGRS: the group‐finding algorithm and the 2PIGG catalogue
Author(s) -
Eke V. R.,
Baugh Carlton M.,
Cole Shaun,
Frenk Carlos S.,
Norberg Peder,
Peacock John A.,
Baldry Ivan K.,
BlandHawthorn Joss,
Bridges Terry,
Can Russell,
Colless Matthew,
Collins Chris,
Couch Warrick,
Dalton Gavin,
Propris Roberto De,
Driver Simon P.,
Efstathiou George,
Ellis Richard S.,
Glazebrook Karl,
Jackson Carole,
Lahav Ofer,
Lewis Ian,
Lumsden Stuart,
Maddox Steve,
Madgwick Darren,
Peterson Bruce A.,
Sutherland Will,
Taylor Keith
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.07408.x
Subject(s) - field galaxy , physics , astrophysics , redshift survey , galaxy , galaxy group , redshift , velocity dispersion , homogeneous , group (periodic table) , astronomy , galaxy cluster , statistical physics , quantum mechanics
The construction of a catalogue of galaxy groups from the Two‐degree Field Galaxy Redshift Survey (2dFGRS) is described. Groups are identified by means of a friends‐of‐friends percolation algorithm which has been thoroughly tested on mock versions of the 2dFGRS generated from cosmological N ‐body simulations. The tests suggest that the algorithm groups all galaxies that it should be grouping, with an additional 40 per cent of interlopers. About 55 per cent of the ∼190 000 galaxies considered are placed into groups containing at least two members of which ∼29 000 are found. Of these, ∼7000 contain at least four galaxies, and these groups have a median redshift of 0.11 and a median velocity dispersion of 260 km s −1 . This 2dFGRS Percolation‐Inferred Galaxy Group (2PIGG) catalogue represents the largest available homogeneous sample of galaxy groups. It is publicly available on the World Wide Web.