Groups: The rich, the poor and the destitute

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


I discuss recent observational results that suggest an evolutionary path for groups in which galaxy tidal interactions and mergers strip stars, dark matter, and gas from galaxies. As the group evolves, its velocity dispersion increases, the brightest group galaxy grows and moves toward the center of the potential, other giant galaxies merge, concentrating and/or creating their dwarf satellite populations, group members evolve from late to early types, and intragroup stars are drawn out of their host galaxies. Dark matter and gas are stripped from the galaxies' outer halos and dispersed into a common group halo. The ultimate evolution of this group may be an isolated elliptical or "fossil group". In this process, some evolved groups acquire the characteristics of rich clusters. Given that clusters themselves evolve via the accretion of poor groups from the field, there is evidence that galaxy evolution in groups dominates the evolution of the galaxies that ultimately end up as cluster members and that evolutionary mechanisms associated with clusters, such as ram pressure stripping or strangulation, are relatively unimportant.

Original languageEnglish (US)
Title of host publicationGroups of Galaxies in the Nearby Universe
Subtitle of host publicationProceedings of the ESO Workshop held at Santiago de Chile, December 5-9, 2005
EditorsIvo Saviane, Valentin Ivanov, Jordanka Borissova
Number of pages11
StatePublished - 2007

Publication series

NameESO Astrophysics Symposia
ISSN (Print)1431-2433
ISSN (Electronic)1611-6143

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Physics and Astronomy (miscellaneous)


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