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The colours of satellite galaxies in groups and clusters

Font, A.S.; Bower, R.G.; McCarthy, I.G.; Benson, A.J.; Frenk, C.S.; Helly, J.C.; Lacey, C.G.; Baugh, C.M.; Cole, S.

The colours of satellite galaxies in groups and clusters Thumbnail


A.S. Font

R.G. Bower

I.G. McCarthy

A.J. Benson

J.C. Helly


Current models of galaxy formation predict satellite galaxies in groups and clusters that are redder than observed. We investigate the effect on the colours of satellite galaxies produced by the ram-pressure stripping of their hot-gaseous atmospheres as the satellites orbit within their parent halo. We incorporate a model of the stripping process based on detailed hydrodynamic simulations within the Durham semi-analytic model of galaxy formation. The simulations show that the environment in groups and clusters is less aggressive than previously assumed. The main uncertainty in the model is the treatment of gas expelled by supernovae. With reasonable assumptions for the stripping of this material, we find that satellite galaxies are able to retain a significant fraction of their hot gas for several Gyr, thereby replenishing their reservoirs of cold, star-forming gas and remaining blue for a relatively long period of time. A bimodal distribution of galaxy colours, similar to that observed in Sloan Digital Sky Survey data, is established and the colours of the satellite galaxies are in good agreement with the data. In addition, our model naturally accounts for the observed dependence of satellite colours on environment, from small groups to high-mass clusters.


Font, A., Bower, R., McCarthy, I., Benson, A., Frenk, C., Helly, J., …Cole, S. (2008). The colours of satellite galaxies in groups and clusters. Monthly Notices of the Royal Astronomical Society, 389(4), 1619-1629.

Journal Article Type Article
Publication Date Oct 1, 2008
Deposit Date Jan 31, 2012
Publicly Available Date Jan 4, 2013
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 389
Issue 4
Pages 1619-1629
Keywords Galaxies, Clusters, Evolution, Fundamental parameter, Luminosity function, Mass.


Published Journal Article (782 Kb)

Copyright Statement
This article has been published in the Monthly Notices of the Royal Astronomical Society
© 2008 The Authors.
Published by Oxford University Press on behalf of The Royal Astronomical Society. All rights reserved.

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