Volume 540, April 2012
|Number of page(s)||9|
|Section||Catalogs and data|
|Published online||05 April 2012|
Groups and clusters of galaxies in the SDSS DR8
1 Tartu Observatory, Observatooriumi 1, 61602 Tõravere, Estonia
2 National Institute of Chemical Physics and Biophysics, Rävala pst 10, 10143 Tallinn, Estonia
3 Institute of Physics, Tartu University, Tähe 4, 51010 Tartu, Estonia
Received: 20 December 2011
Accepted: 19 February 2012
Aims. We intend to compile a new galaxy group and cluster sample of the latest available SDSS data, adding several parameter for the purpose of studying the supercluster network, galaxy and group evolution, and their connection to the surrounding environment.
Methods. We used a modified friends-of-friends (FoF) method with a variable linking length in the transverse and radial directions to eliminate selection effects and to find reliably as many groups as possible. Using the galaxies as a basis, we calculated the luminosity density field.
Results. We create a new catalogue of groups and clusters for the SDSS data release 8 sample. We find and add environmental parameters to our catalogue, together with other galaxy parameters (e.g., morphology), missing from our previous catalogues. We take into account various selection effects caused by a magnitude limited galaxy sample. Our final sample contains 576 493 galaxies and 77 858 groups.
Key words: catalogs / galaxies: clusters: general / galaxies: groups: general / galaxies: statistics / large-scale structure of Universe / cosmology: observations
The group catalogue is available at http://www.aai.ee/~elmo/dr8groups/ and at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (220.127.116.11) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/540/A106
© ESO, 2012
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