The 2dF Galaxy Redshift Survey: a targeted study of catalogued clusters of galaxies |
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| Authors: | Roberto De Propris Warrick J Couch Matthew Colless Gavin B Dalton Chris Collins Carlton M Baugh Joss Bland-Hawthorn Terry Bridges Russell Cannon Shaun Cole Nicholas Cross Kathryn Deeley Simon P Driver George Efstathiou Richard S Ellis Carlos S Frenk Karl Glazebrook Carole Jackson Ofer Lahav Ian Lewis Stuart Lumsden Steve Maddox Darren Madgwick Stephen Moody Peder Norberg John A Peacock Will Percival Bruce A Peterson Will Sutherland Keith Taylor |
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| Institution: | 1Department of Astrophysics, University of New South Wales, Sydney, NSW 2052, Australia;2Research School of Astronomy and Astrophysics, The Australian National University, Weston Creek, ACT 2611, Australia;3Department of Physics, Keble Road, Oxford OX1 3RH;4Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Birkenhead L14 1LD;5Department of Physics, South Road, Durham DH1 3LE;6Anglo-Australian Observatory, PO Box 296, Epping, NSW 2121, Australia;7School of Physics and Astronomy, North Haugh, St Andrews, Fife KY6 9SS;8Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA;9Department of Astronomy, Caltech, Pasadena, CA 91125, USA;10Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218-2686, USA;11Racah Institute of Physics, The Hebrew University, Jerusalem, 91904, Israel;12Department of Physics, University of Leeds, Woodhouse Lane, Leeds LS2 9JT;13School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD;14Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ |
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| Abstract: | We have carried out a study of known clusters within the 2dF Galaxy Redshift Survey (2dFGRS) observed areas and have identified 431 Abell, 173 APM and 343 EDCC clusters. Precise redshifts, velocity dispersions and new centroids have been measured for the majority of these objects, and this information is used to study the completeness of these catalogues, the level of contamination from foreground and background structures along the cluster's line of sight, the space density of the clusters as a function of redshift, and their velocity dispersion distributions. We find that the Abell and EDCC catalogues are contaminated at the level of about 10 per cent, whereas the APM catalogue suffers only 5 per cent contamination. If we use the original catalogue centroids, the level of contamination rises to approximately 15 per cent for the Abell and EDCC catalogues, showing that the presence of foreground and background groups may alter the richness of clusters in these catalogues. There is a deficiency of clusters at  that may correspond to a large underdensity in the Southern hemisphere. From the cumulative distribution of velocity dispersions for these clusters, we derive a space density of  clusters of  This result is used to constrain models for structure formation; our data favour low-density cosmologies, subject to the usual assumptions concerning the shape and normalization of the power spectrum. |
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| Keywords: | astronomical data bases: miscellaneous surveys galaxies: clusters: general galaxies: distances and redshifts cosmology: observations |
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