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The age dependence of galaxy clustering

Reed, Darren S. ; Governato, Fabio ; Quinn, Thomas ; Stadel, Joachim ; Lake, George

In: Monthly Notices of the Royal Astronomical Society, 2007, vol. 378, no. 2, p. 777-784

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    Titre
    • The age dependence of galaxy clustering
    Auteur
    • Reed, Darren S.. Institute for Computational Cosmology, Department of Physics, University of Durham, South Road, Durham DH1 3LE
    • Governato, Fabio. Astronomy Department, Box 351580, University of Washington, Seattle, WA 98195, USA
    • Quinn, Thomas. Astronomy Department, Box 351580, University of Washington, Seattle, WA 98195, USA
    • Stadel, Joachim. Institute for Theoretical Physics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
    • Lake, George. Institute for Theoretical Physics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
    Type de document
    • Postprint
    Langue
    • Inglese
    Publié dans
    • Monthly Notices of the Royal Astronomical Society, 2007, vol. 378, no. 2, p. 777-784. Blackwell Publishing Ltd
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:293758
    Summary
    We construct mock galaxy catalogues to analyse clustering properties of a Λ cold dark matter universe within a cosmological dark matter simulation of sufficient resolution to resolve structure down to the scale of dwarfs. We show that there is a strong age-clustering correlation for objects likely to host luminous galaxies, which includes the satellite halo (subhalo) population. Older mock galaxies are significantly more clustered in our catalogue, which consists of satellite haloes as well as the central peaks of discrete haloes, selected solely by peak circular velocity. This age dependence is caused mainly by the age-clustering relation for discrete haloes, recently found by Gao et al., acting mostly on field members, combined with the tendency for older mock galaxies to lie within groups and clusters, where galaxy clustering is enhanced. Our results suggest that the clustering-age dependence is manifested in real galaxies. At small scales (less than ∼5 h−1 Mpc), the very simple assumption that galaxy colour depends solely on halo age is inconsistent with the strength of the observed clustering colour trends, where red galaxies become increasingly more clustered than blue galaxies towards smaller scales, suggesting that luminosity-weighted galaxy ages do not closely trace the assembly epoch of their dark matter hosts. The age dependence is present but is much weaker for satellite haloes lying within groups and clusters than for the global population