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The Multiplicity Function of Galaxies

E. Puddu·E. De Filippis·G. Longo·S. Andreon·R. R. Gal
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Abstract

The multiplicity function (MF) of groups and clusters of galaxies is determined using galaxy catalogues extracted from a set of Digitized Palomar Sky Survey (DPOSS) plates. The two different types of structures (of low and high richness) were identified using two different algorithms: a modified version of the van Albada method for groups, and a peak finding algorithm for larger structures. In a 300 sq. deg. area up to z<0.2, we find 2944 groups and 179 clusters. Our MF covers a wide range of richnesses, from 2 to 200, and the two MF's derived by the two algorithms match smoothly without the need for additional conditions or normalisations. The resulting multiplicity function, of slope alpha= -2.08 +- 0.07, strongly resembles a power law.

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E. Puddu, E. De Filippis, G. Longo, S. Andreon, R. R. Gal. 2003-02-06. The Multiplicity Function of Galaxies. https://doi.org/10.1051/0004-6361%3A20030254

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