Forum Springer Astron. Astrophys.
Forum Whats New Search Orders

Astron. Astrophys. 357, 809-815 (2000)

Table of Contents
Available formats: HTML | PDF | (gzipped) PostScript

Non radial motions and the shapes and the abundance of clusters of galaxies

A. Del Popolo 1,2 and M. Gambera 1,3

1 Istituto di Astronomia dell'Università di Catania, Viale A. Doria 6, 95125 Catania, Italy
2 Università Statale di Bergamo, Dipartimento di Matematica, Piazza Rosate 2, 24129 Bergamo, Italy
3 Osservatorio Astrofisico di Catania and CNR-GNA, Viale A. Doria 6, 95125 Catania, Italy

Received 4 January 1999 / Accepted 4 January 2000


We study the effect of non-radial motions on the mass function, the velocity dispersion function (hereafter VDF) and on the shape of clusters of galaxies using the model introduced in Del Popolo & Gambera (1998a,b, 1999). The mass function of clusters, obtained using the quoted model, is compared with the statistical data by Bahcall & Cen (1992, 1993) and Girardi et al. (1998), while the VDF is compared with the Center for Astrophysics (hereafter CfA) data by Zabludoff et al. (1993) for local clusters and those of Mazure et al. (1996) and Fadda et al. (1996). In both cases the model predictions are in good agreement with the observational data showing once more how non-radial motions can reduce many of the discrepancies between Cold Dark Matter (hereafter CDM) model predictions and observational data. Finally we study the effect of non-radial motions on the intrinsic shape of clusters of galaxies showing that non-radial motions produce clusters less elongated with respect to CDM model in agreement with de Theije et al. (1995, 1997) results.

Key words: cosmology: theory – cosmology: large-scale structure of Universe – galaxies: formation

Send offprint requests to: M. Gambera (mga@sunct.ct.astro.it)

© European Southern Observatory (ESO) 2000

Online publication: June 5, 2000