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The Distribution of Rich Clusters of Galaxies


Abell, George Ogden (1957) The Distribution of Rich Clusters of Galaxies. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/99X5-ZM38.


A catalogue is prepared of 2712 rich clusters of galaxies found on the National Geographic Society--Palomar Observatory Sky Survey. From the catalogue, 1682 clusters are selected which meet specific criteria for inclusion in a homogeneous statistical sample.

An investigation of the sample leads to the following conclusions: (i) The distribution function of clusters according to richness, N(n) increases rapidly as n decreases. (ii) The data allow no significant decision that the spatial density of cluster centers varies with distance. (iii) Galactic obscuration of the order of a few tenths of a magnitude (photored) exists at high northern galactic latitudes around galactic longitude 300°. (iv) There is a highly significant nonrandom distribution of clusters in direction, both when clusters at all distances and when clusters at various distances are considered. An analysis of the distribution yields strong evidence for the existence of second-order clusters, that is clusters of clusters of galaxies. A statistical test shows the observed distribution to be compatible with the assumption of complete second-order clustering of galaxies.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Astronomy and Physics)
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Astronomy
Minor Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Osterbrock, Donald E.
Group:Astronomy Department
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1957
Record Number:CaltechETD:etd-05022007-092134
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1581
Deposited By: Imported from ETD-db
Deposited On:03 May 2007
Last Modified:15 Aug 2023 19:56

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