Orientations, ellipticities and nearest-neighbor correlations in rich clusters of galaxies

M. P. Ulmer*, S. L.W. McMillan, M. P. Kowalski

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Using the Einstein Observatory data base, we have analyzed X-ray images of rich clusters of galaxies to determine the ellipticity of the images. The basic premise behind this analysis is that if "top-down" scenarios of supercluster/cluster formation hold, then clusters should "point" towards their nearest neighbor rich cluster, if the nearest-neighbor cluster is less than some specific distance away. Optical data hinted that such an effect existed as long as the cluster/nearest- neighbor separation was under about 25 Mpc (Hubble constant = 50 km/sec/Mpc). Our own analysis shows no such effect, which favors "bottom up" scenarios of galaxy/cluster formation.

Original languageEnglish (US)
Pages (from-to)13-15
Number of pages3
JournalAdvances in Space Research
Issue number2
StatePublished - 1990

ASJC Scopus subject areas

  • Aerospace Engineering
  • Astronomy and Astrophysics
  • Geophysics
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences(all)


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