Anisotropic distribution of satellite galaxies

Using mock catalogues generated from cosmological N-body simulations, we demonstrate that the selection criteria used to select isolated galaxies and their satellites in large galaxy redshift surveys must be very strict in order to correctly identify systems in which the primary galaxy dominates its environment.

We demonstrate that the criteria used in many previous studies instead select predominantly group members. We refine a set of selection criteria for which the group contamination is estimated to be less than 7 per cent and present a catalogue of the resulting sample.