Correlation analysis of objectively defined galaxy and cluster catalogues.
Abstract
We present further galaxy clustering results from the objective COSMOS/UKST galaxy catalogue of Stevenson et at. We first reexamine the results of SSFM for the galaxy correlation function, w_gg_(θ), testing the stability of the result against possible systematic effects and extending the analysis to larger angular scales. The results support the observation of a `break' from the powerlaw behaviour of what angular scales corresponding to a spatial separation of 35 h^1^ Mpc, although the feature is only significant at the 2σ, level. At larger scales (>~6h^1^ Mpc) w_gg_ shows no significant evidence of clustering. We then use the method of Turner & Gott to automatically detect groups and clusters in these catalogues. The clustercluster angular correlation function, w_cc_, is calculated and found to have significantly higher amplitude than for galaxies at the same average depth, the result for our richest clusters being consistent with that found by Hauser & Peebles from a study of rich Abell clusters. Using our greater variety of cluster types tentative evidence is also obtained for the amplitude of w_cc_ being a function of cluster richness. We next present the clustergalaxy crosscorrelation function w_cg_. The result for our richest clusters is consistent with the w_cg_ obtained by Seldner & Peebles in an analysis of the Lick and Abell catalogues. However, if lessrich groups are included a slightly flatter slope is obtained. Finally, the above correlation analyses are carried out on simulated galaxy and cluster catalogues. The results show that interpreting the cluster correlation functions may not be straightforward and that statistical biasing and the nature of the group detection algorithm may be factors as important for the amplitude of w_cc_ and w_cg_ as the actual strength of largescale clustering.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 October 1988
 DOI:
 10.1093/mnras/234.3.801
 Bibcode:
 1988MNRAS.234..801S
 Keywords:

 Astronomical Catalogs;
 Computational Astrophysics;
 Galactic Clusters;
 Galaxies;
 Angular Correlation;
 Cross Correlation;
 Data Simulation;
 Photographic Plates;
 Statistical Analysis;
 Astrophysics